Brazing filler metal

ABSTRACT

A brazing filler metal is composed of gold, silver, copper, and an additive element including at least one kind of element out of aluminum, bismuth, gallium, germanium, indium, antimony, silicon, tin, lead, tellurium, and thallium, as main constituents thereof, wherein a total composition ratio of the additive element is in a range of more than 1 wt. % to less than 36 wt. %, and a composition ratio of the gold is less than 80 wt. %, and a composition ratio of the silver is less than 42 wt. %, so that the brazing filler metal joins metals for use as members of which decorativeness in external appearance is required, such as stainless steel and so on, at a low temperature which does not cause the crystal structure thereof to be coarsened, while securing excellent corrosion resistance and sufficient joining strength.

TECHNICAL FIELD

[0001] The invention relates to a brazing filler metal with whichbrazing having excellent corrosion resistance and sufficient joiningstrength can be implemented, and in particular, to a brazing fillermetal which is suitable for use in brazing of metals of whichdecorativeness in external appearance is required, such as stainlesssteel, titanium metal, and titanium alloy, and with which brazing can beimplemented at a temperature which does not cause the crystal structurethereof to be coarsened.

BACKGROUND TECHNOLOGY

[0002] Brazing has been known for ages as one of metalworking techniqueswhereby mating metals can be joined with each other with relative ease.Since brazing is among important metalworking techniques of even today,it is applied to a wide variety of industrial sectors, and kinds ofbrazing filler metal for use in the brazing cover a broad spectrum.

[0003] For some kinds of metals and their alloy, however, there has notbeen found an effective brazing filler metal as yet. Stainless steel isone of such metals. As stainless steel has excellent properties such asless corrosiveness because of high corrosion resistance and highresistance to acid and heat, it is in widespread use in variousindustrial sectors, and is used even for metallic articles (for example,a wrist watch, the frame of eyeglasses) of which decorativeness inexternal appearance is required.

[0004] By the way, as described in an article titled “Story of StainlessSteel” compiled by Japan Institute Standards Organization (issued byJapan Institute Standards Organization Press), silver solder and nickelsolder have been well known as conventional brazing filler metals foruse in brazing of members made of stainless steel (referred tohereinafter merely as “stainless steel members”).

[0005] Silver solder as a brazing filler metal has its own melting pointin a range of from about 800 to 1000° C. Examples of a brazing fillermetal include a brazing filler metal with which brazing can be executedat a temperature not higher than 800° C., for example, BAg-8 (meltingpoint: 780° C.) according to the JIS specification, which is at timesput to use in brazing of the stainless steel members. However, such abrazing filler metal as described is not in much use for brazing infabrication of metallic articles such as a wrist watch, and the frame ofeyeglasses, of which decorativeness in external appearance is required,because the brazing filler metal has poor corrosion resistance and isprone to initiation of corrosion of the stainless steel members afterbrazing.

[0006] Examples of nickel solder include BNi-2 (melting point: 1000° C.)according to the JIS specification. Normally, there occurs no coarseningof the crystal structure in a reducing atmosphere such as hydrogen atabout not higher than 800° C. In this case, however, since this brazingfiller metal has a high melting point which is higher than 800° C.,brazing is executed using this brazing filler metal, thereby causing thecrystal structure of the brazed stainless steel members to be coarsened.Accordingly, in the case of brazing the stainless steel members withBNi-2, there is the need for taking steps of removing coarsened portionsof the crystal structure thereof by grinding, and so forth, andsubsequently applying thereto mirror-finish, and the like. It should benoted that members to be brazed which are objects of brazing are called“base metals” in the following description, which mainly denotestainless steel members in the invention. When stainless steel is usedas base metals, the “crystal coarsening temperature of the base metals”in this case is set at 800° C.

[0007] On the other hand, a brazing filler metal (melting point: 1000 to1200° C.) containing Cr, Fe, Si, and Ni as main constituents thereofsuitable for stainless steel is disclosed in JP 61-10235, A, whichdiscloses that brazing was implemented at 1050 to 1250° C. using thebrazing filler metal. This brazing filler metal, however, also has amelting point not lower than the crystal coarsening temperature of thebase metals, thus causing the crystal structure of the stainless steelmembers to be coarsened after brazing.

[0008] As a method of joining stainless steel members together, weldingis in widespread use besides brazing. Welding has no problem in respectof joining strength and corrosion resistance, however, there emergespots where the stainless steel members need to be heated locally to ahigh temperature for implementing joining. As a result, there haveemerged spots where a temperature is in excess of the crystal coarseningtemperature of the base metals, causing the crystal structure thereof tobe coarsened, so that welding has a drawback in that portions of thestainless steel members, worked on by welding, require post-working.Also, there are times when projection welding is applied for joining ofstainless steel members whereby welding is executed by causing electriccurrent to flow through projections of the stainless steel members,formed for the purpose of welding. The projection welding, however, hashad a drawback in that, if the stainless steel members to be joined witheach other are complex in construction, it becomes difficult to causeuniform concentration of electric current on the projections of thestainless steel members, thus resulting in difficulty with welding.

[0009] As described in the foregoing, conventional techniques forjoining the stainless steel members have not offered any joiningtechniques capable of securing excellent corrosion resistance andsufficient joining strength, and further, capable of implementingjoining at a temperature which does not cause the crystal structurethereof to be coarsened.

[0010] The invention has been developed to solve the problems asdescribed above, and it is an object of the invention to provide abrazing filler metal for use in brazing of metals such as stainlesssteel, used in members of which decorativeness in external appearance isrequired, wherein brazing can be implemented at a temperature which doesnot cause the crystal structure thereof to be coarsened while securingexcellent corrosion resistance and sufficient joining strength.

DISCLOSURE OF THE INVENTION

[0011] A brazing filler metal according to the invention has acomposition comprising gold, silver, copper, and an additive elementcomprising at least one kind of element out of aluminum, bismuth,gallium, germanium, indium, antimony, silicon, tin, lead, tellurium, andthallium, as main constituents thereof, wherein a total compositionratio of the additive element from more than 1 wt. % to less than 36 wt.%, and a composition ratio of the gold is less than 80 wt. %, and acomposition ratio of the silver is less than 42 wt. %.

[0012] With the above-described brazing filler metal, the totalcomposition ratio of the additive element is preferably in a range ofabout 2 to about 35 wt. %.

[0013] Further, in the above-described brazing filler metal, it ispreferable that the composition ratio of the gold is more than 34 wt. %,and the composition ratio of the silver is more than 5 wt. %. Thecomposition ratio of the silver is preferably in a range of about 6 toabout 41 wt. %.

[0014] Furthermore, it is more preferable that the composition ratio ofthe gold is in a range of about 47 to about 64 wt. %, and thecomposition ratio of the silver is in a range of about 6 to about 20 wt.%.

[0015] This invention provides a brazing filler metal having acomposition comprising gold, silver, copper, and germanium, as mainconstituents thereof, wherein a composition ratio of the germanium is ina range of more than 4 wt. % to less than 24 wt. %, and a compositionratio of the gold is more than 34 wt. %, and a composition ratio of thesilver is less than 41 wt. %.

[0016] With this brazing filler metal, the composition ratio of thegermanium is preferably in a range of about 5 to about 23 wt. %.

[0017] Further, it is preferable that the composition ratio of the goldis in a range of about 35 to about 80 wt. %, the composition ratio ofthe silver is in a range of about 5 to about 40 wt. %, and thecomposition ratio of the germanium is in a range of about 10 to about 19wt. %. Further more, the composition ratio of the silver is preferablyin a range of about 6 to about 40 wt. %.

[0018] This invention also provides a brazing filler metal having acomposition comprising gold, silver, copper, and silicon, as mainconstituents' thereof, wherein a composition ratio of the silicon is ina range of more than 0.9 wt. % to less than 19 wt. %, a compositionratio of the gold is more than 40 wt. %, and a composition ratio of thesilver is in a range of more than 4 wt. % to less than 37 wt. %.

[0019] With this brazing filler metal, the composition ratio of thesilicon is in a range of about 1 to about 18 wt. %. Further, it ispreferable that the composition ratio of the gold is in a range of about41 to about 79 wt. %, and the composition ratio of the silver is in arange of about 5 to about 36 wt. %.

[0020] This invention also provides a brazing filler metal having acomposition comprising gold, silver, copper, and at least any one kindof element out of germanium, silicon, and tin, as main constituentsthereof, wherein a total composition ratio of the germanium, silicon,and tin is in a range of more than 1 wt. % to less than 35 wt. %, acomposition ratio of the gold is less than 80 wt. %, and a compositionratio of the silver is less than 42 wt. %.

[0021] With this brazing filler metal, the total composition ratio ofthe germanium, silicon, and tin is preferably in a range of about 2 toabout 34 wt. %. Further, it is preferable that the composition ratio ofthe gold is in a range of about 47 to about 64 wt. %, and thecomposition ratio of the silver is in a range of about 6 to about 20 wt.%.

[0022] This invention also provides a brazing filler metal having acomposition comprising gold, silver, copper, palladium, and an additiveelement comprising at least one kind of element out of aluminum,bismuth, gallium, germanium, indium, antimony, silicon, tin, lead,tellurium, and thallium, as main constituents thereof, wherein a totalcomposition ratio of the additive element is in a range of more than 1wt. % to less than 38 wt. %, a composition ratio of the gold is lessthan 82 wt. %, a composition ratio of the palladium is less than 34 wt.%, and a composition ratio of the silver is less than 47 wt. %.

[0023] With the above-described brazing filler metal, the compositionratio of the palladium is preferably not more than about 33 wt. %.

[0024] Further, in the above-described brazing filler metal, it ispreferable that the composition ratio of the gold is more than 33 wt. %,and the composition ratio of the silver is more than 4 wt. %.Furthermore, it is preferable that the composition ratio of the gold isin a range of about 51 to about 56 wt. %, and the composition ratio ofthe silver is in a range of about 5 to about 20 wt. %.

[0025] This invention also provides a brazing filler metal having acomposition comprising gold, silver, copper, palladium, a first additiveelement comprising at least one kind of element out of aluminum,bismuth, gallium, germanium, indium, antimony, silicon, tin, lead,tellurium, and thallium, and a second additive element comprising atleast one element out of lithium and manganese, as main constituentsthereof, wherein a total composition ratio of the first additive elementis in a range of more than 1 wt. % to less than 38 wt. %, a compositionratio of the gold is less than 78 wt. %, a total composition ratio ofthe second additive element is less than 3 wt. %, a composition ratio ofthe palladium is less than 32 wt. %, and a composition ratio of thesilver is less than 48 wt. %.

[0026] With this brazing filler metal, the total composition ratio ofthe first additive element is preferably in a range of about 2 to about37 wt. %.

[0027] Further, with this brazing filler metal, the composition ratio ofthe gold is preferably more than 33 wt. %, and the composition ratio ofthe silver is preferably more than 5 wt. %. Furthermore, it ispreferable that the composition ratio of the gold is in a range of about34 to about 77 wt. %, and the composition ratio of the silver is in arange of about 6 to about 47 wt %.

[0028] Further, this invention also provides a brazing filler metalhaving a composition comprising gold, silver, copper, palladium, nickel,a first additive element comprising at least one kind of element out ofaluminum, bismuth, gallium, germanium, indium, antimony, silicon, tin,lead, tellurium, and thallium, and a second additive element comprisingat least one element out of lithium and manganese, as main constituentsthereof, wherein a total composition ratio of the first additive elementis in a range of more than 1 wt. % to less than 35 wt. %, a compositionratio of the gold is less than 74 wt. %, a total composition ratio ofthe second additive element is less than 3 wt. %, a composition ratio ofthe palladium is less than 31 wt. %, a composition ratio of the nickelis less than 16 wt. %, and a composition ratio of the silver is lessthan 47 wt. %.

[0029] With this brazing filler metal, the total composition ratio ofthe first additive element is preferably in a range of about 2 to about34 wt. %. Further, it is preferable that the composition ratio of thegold is more than 35 wt. %, and the composition ratio of the silver ismore than 6 wt. %. Furthermore, it is preferable that the compositionratio of the gold is in a range of about 36 to about 73 wt. %, and thecomposition ratio of the silver is in a range of about 7 to about 46 wt.%.

[0030] Moreover, this invention also provides a brazing filler metalhaving a composition comprising gold, silver, copper, palladium, andgermanium, as main constituents thereof, wherein a composition ratio ofthe germanium is in a range of more than 4 wt. % to less than 26 wt. %,a composition ratio of the gold is in a range of more than 28 wt. % toless than 76 wt. %, a composition ratio of the palladium is less than 36wt. %, and a composition ratio of the silver is less than 51 wt. %.

[0031] With brazing filler metal, the composition ratio of the germaniumis preferably in a range of about 5 to about 25 wt. %. Further, it ispreferable that the composition ratio of the gold is in a range of about29 to about 75 wt. %, and the composition ratio of the silver is in arange of about 5 to about 50 wt. %.

[0032] Further, this invention also provides a brazing filler metalhaving a composition comprising gold, silver, copper, palladium, andsilicon, as main constituents thereof, wherein a composition ratio ofthe silicon is in a range of more than 0.9 wt. % to less than 17 wt. %,a composition ratio of the gold is in a range of more than 30 wt. % toless than 72 wt. %, a composition ratio of the palladium is less than 38wt. %, and a composition ratio of the silver is in a range of more than2 wt. % to less than 34 wt. %.

[0033] With this brazing filler metal, the composition ratio of thesilicon is preferably in a range of about 1 to about 16 wt. %. Further,it is desirable that the composition ratio of the gold is in a range ofabout 40 to about 71 wt. %, the composition ratio of the silver is in arange of about 3 to about 32 wt. %, and the composition ratio of thepalladium is in a range of about 5 to about 37 wt. %.

[0034] Furthermore, this invention also provides a brazing filler metalhaving a composition comprising gold, silver, copper, palladium, and atleast any one kind of element out of germanium, silicon, and tin, asmain constituents thereof, wherein a total composition ratio of thegermanium, silicon, and tin is in a range of more than 1 wt. % to lessthan 38 wt. %, a composition ratio of the gold is less than 83 wt. %, acomposition ratio of the palladium is less than 35 wt. %, and acomposition ratio of the silver is less than 49 wt. %.

[0035] With this brazing filler metal, the total composition ratio ofthe germanium, silicon, and tin is preferably in a range of about 2 toabout 37 wt. %. Further, it is preferable that the composition ratio ofthe gold is in a range of about 53 to about 56 wt. %, and thecomposition ratio of the silver is in a range of about 5 to about 18 wt.%.

[0036] Further, this invention is preferably a brazing filler metalhaving a composition comprising gold, silver, copper, palladium, nickel,and at least any one kind of element out of germanium, silicon, and tin,as main constituents thereof, wherein a total composition ratio of thegermanium, silicon, and tin is in a range of more than 1 wt. % to lessthan 37 wt. %, a composition ratio of the gold is less than 74 wt. %, acomposition ratio of the palladium is less than 27 wt. %, a compositionratio of the nickel is less than 18 wt. %, and a composition ratio ofthe silver is less than 47 wt. %.

[0037] Further, the total composition ratio of the germanium, silicon,and tin is preferably in a range of about 2 to about 36 wt. %. It ismore desirable that the composition ratio of the gold is in a range ofabout 52 to about 54 wt. %, and the composition ratio of the silver isin a range of about 5 to about 19 wt. %.

BRIEF DESCRIPTION OF THE DRAWINGS

[0038]FIG. 1 is a perspective view showing a case fabricated by joiningfour pieces of watch appearance portions to a case body;

[0039]FIG. 2 is a disassembly view showing the case body and the fourpieces of the watch appearance portions before joining the four piecesof the watch appearance portions to the case body;

[0040]FIG. 3 is a plan view showing a metallic member consisting of twostainless steel sheets, overlapped so as to cross each other;

[0041]FIG. 4 is a sectional view taken on line 4-4 in FIG. 3;

[0042]FIG. 5 is a sectional view of one of the watch appearance portionsshown in FIG. 1, cut along a plane containing an end-piece hole;

[0043]FIG. 6 is a phase diagram of a binary system of Ag—Au, thehorizontal axis thereof showing a composition ratio of Au to Ag whilethe vertical axis thereof showing a melting point;

[0044]FIG. 7 is a phase diagram of a binary system of Cu—Au, thehorizontal axis thereof showing a composition ratio of Au to Cu whilethe vertical axis thereof showing a melting point;

[0045]FIG. 8 is a phase diagram of a binary system of Ag—Cu, thehorizontal axis thereof showing a composition ratio of Cu to Ag whilethe vertical axis thereof showing a melting point;

[0046]FIG. 9 is a phase diagram of a binary system of Au—Ge, thehorizontal axis thereof showing a composition ratio of Ge to Au whilethe vertical axis thereof showing a melting point;

[0047]FIG. 10 is a phase diagram of a binary system of Au—Si, thehorizontal axis thereof showing a composition ratio of Si to Au whilethe vertical axis thereof showing a melting point;

[0048]FIG. 11 is a phase diagram of a binary system of Au—Sn, thehorizontal axis thereof showing a composition ratio of Sn to Au whilethe vertical axis thereof showing a melting point;

[0049]FIG. 12 is a phase diagram of a binary system of Ag—Ge, thehorizontal axis thereof showing a composition ratio of Ag to Ge whilethe vertical axis thereof showing a melting point;

[0050]FIG. 13 is a phase diagram of a binary system of Cu—Ge, thehorizontal axis thereof showing a composition ratio of Cu to Ge whilethe vertical axis thereof showing a melting point;

[0051]FIG. 14 is a phase diagram of a binary system of Si—Ag, thehorizontal axis thereof showing a composition ratio of Ag to Si whilethe vertical axis thereof showing a melting point;

[0052]FIG. 15 is a phase diagram of a binary system of Ag—Sn, thehorizontal axis thereof showing a composition ratio of Sn to Ag whilethe vertical axis thereof showing a melting point; and

[0053]FIG. 16 is a phase diagram of a, binary system of Ge—Pd, thehorizontal axis thereof showing a composition ratio of Pd to Ge whilethe vertical axis thereof showing a melting point.

BEST MODE FOR CARRYING OUT THE INVENTION

[0054] Embodiments of a brazing filler metal according to the inventionare described in detail hereinafter with reference to the accompanyingdrawings.

[0055] (First Brazing Filler Metal)

[0056] Firstly, a Au—Ag—Cu based brazing filler metal which is a firstbrazing filler metal according to the invention is describedhereinafter. The Au—Ag—Cu based brazing filler metal is composed of, asmain constituents, gold (Au), metals having homogeneous solubility withAu, and an additive element composed of elements of metal orsemiconductor. As the metals having homogeneous solubility with Au,silver (Ag), and copper (Cu) are used in this embodiment. Besides, asthe additive element, at least one kind of element is used which isselected from among aluminum (Al), bismuth (Bi), gallium (Ga), germanium(Ge), indium (In), antimony (Sb), silicon (Si), tin (Sn), lead (Pb),tellurium (Te), and thallium (Tl). The Au—Ag—Cu based brazing fillermetal is produced by the following process. The process comprises thesteps of firstly weighing respective quantities of Au, Ag, Cu, and theadditive element such that composition ratios as desired are obtained,respectively, and producing an alloy by melting the respective metals bymeans of the vacuum melting process. Subsequently, the alloy issubjected to working into a slender foil-like shape (ribbon-like shape)about 60 μm thick in an argon (Ar) atmosphere.

[0057] Now, 12 samples being Examples numbered from 1-1 to 1-12 shown inTable 1 and 8 samples being Comparative Examples numbered from 1-1 to1-8 shown in Table 2, 20 samples, in total, of different Au—Ag—Cu basedbrazing filler metals, were prepared by varying a composition ratio (wt.%) of each of Au, Ag, and Cu as appropriate as well as varying the kindand a composition ratio (wt. %) of each of the elements constituting theadditive element as appropriate. In this event, the samples wereprepared using one kind of element out of Si, Te, and Bi and using twoor more kinds of elements out of them as the additive element. The twoor more kinds of elements of the additive element are as follows:

[0058] Si and In (Examples 1-2, 1-7 to 1-9, and Comparative Examples 1-5and 1-6

[0059] Ge, Al, and Sb (Example 1-3); Ge, In, and Ga (Example 1-4)

[0060] Bi, Sn, and Te (Example 1-5)

[0061] Pb, Si, and Tl (Example 1-6 and Comparative Example 1-3)

[0062] Al, In, and Te (Comparative Example 1-4)

[0063] Ge and Sb (Examples 1-10 to 1-12 and Comparative Examples 1-7 and1-8)

[0064] To examine properties of the respective prepared samples, brazingwas implemented using as the base metals stainless steel members whosematerial is set to SUS316L. The selected properties of the respectivesamples are six items from a) to f) shown in Table 1 and Table 2, thatis, a) melting point (° C.), b) brazing temperature (° C.), c)wettability against SUS316L, d) crystal coarsening of SUS316L, e)joining strength (MPa), and f) corrosion resistance. The samples whichare considered as suitable brazing filler metals as the object of theinvention are set to be Examples and the samples whose properties arecompared with those of the respective Examples are set to be ComparativeExamples. Note that e) joining strength and f) corrosion resistance arechecked by conducting the following tests.

[0065] (Joining Strength Tests and Corrosion Resistance Tests of BrazingFiller Metals)

[0066] A metallic member 17 shown in FIG. 3 was produced to conduct thejoining strength and corrosion resistance tests of the brazing fillermetals thereon. The metallic member 17 is produced as follows: firstly,two stainless steel sheets, 15, 16, each about 25 mm in length×about 5mm in width×about 1 mm in thickness, are overlapped so as to cross eachother, and a brazing filler metal 19 is sandwiched between the twostainless steel sheets 15, 16 at an intersection 18 where the twostainless steel sheets 15, 16 are in contact with each other. As thebrazing filler metal 19, each of the above-described 20 samples is used.The intersections 18 were secured with a tool (not shown), andsubsequently the two stainless steel sheets 15, 16 were heated atrespective brazing temperatures shown in Tables 1 and 2, respectivelyfor ten minutes and then rapidly cooled in a hydrogen reducingatmosphere. Thereby, 20 patterns of the metallic member 17 are preparedusing the respective samples.

[0067] Joining strength was measured by conducting a tensile testwhereby the stainless steel sheets 15, 16 were pulled in the directionof thickness, a and b, respectively, by use of a tool (not shown).Corrosion resistance was checked by conducting the CASS test specifiedby IS03370 on the respective Samples of the metallic member 17.

[0068] Further, for the sake of comparison, the metallic member 17 wereprepared by the previously described procedure, as the brazing filler19, using nickel solder (82.45 wt. % of Ni, 7 wt. % of Cr, 3 wt. % of B,4.5 wt. % of Si, 3 wt. % of Fe, and 0.05 wt. % of C) and silver solder(58 wt. % of Ag, 32 wt. % of Cu, and 10 wt. % of Pd) well known as theconventional brazing filler metals and corrosion resistance tests andjoining strength tests were conducted thereon. The results of such testsare shown in Table 3. In Table 3, a number affixed to a symbol for therespective metal elements indicates the composition ratio of therespective elements composing the respective brazing filler metals. Forexample, in the case of Comparative Example 1-10, the composition ratioof Ag is 58 wt. %, that of Cu 32 wt. %, and that of Pd 10 wt. %.

[0069] As shown in Table 3, the melting points of the conventionalbrazing filler metals exceed 800° C. In contrast to these, the meltingpoint of any of the brazing filler metals of Examples 1-1 to 1-12 wasnot higher than 800° C. as shown in Table 1, and the brazingtemperatures for these were also not higher than 800° C. The meltingpoints of the brazing filler metals of Comparative Examples 1-1 to 1-4and 1-6, however, exceeded 800° C. as shown in Table 2, and theirbrazing temperatures also exceeded 800° C. (when the melting pointexceeded 800° C., crystal of SUS316L was caused to be coarsened in anyof the samples). Regarding the wettability against SUS316L, while all ofthe samples of Examples 1-1 to 1-12 provided excellent results, thesamples of Comparative Examples 1-1 to 1-7 provided just slightly goodresults which were not sufficient. Besides, coarsening of crystalstructure of SUS316L occurred in any of the conventional brazing fillermetals (Comparative Examples 1-9 and 1-10) and also in ComparativeExamples 1-1 to 1-4 and 1-6. In contrast to this, coarsening of crystalstructure was not seen in any of Examples 1-1 to 1-12. The joiningstrengths of Examples were 590 MPa even at the minimum, and any of themwas better than those of the conventional brazing filler metals.Regarding the corrosion resistance, Examples 1-1 to 1-12 and ComparativeExamples other than Comparative Example 1-8 exhibited excellent results.

[0070] It can be said on the basis of the results shown in Table 1 toTable 3 that the composition ratios of the respective metal elements,that is, Au, Ag, and Cu, and the kind of additive element and thecomposition ratio thereof, necessary for the respective Au—Ag—Cu basedbrazing filler metals to conform to the brazing filler metal as theobject of the invention are as follows:

[0071] Firstly, to conform to the brazing filler metal as the object ofthe invention, each of the Au—Ag—Cu based brazing filler metals needs tohave a melting point below the crystal coarsening temperature of thebase metals and be able to join the base metals at a low temperature(referred to hereinafter as low temperature joining) which does notcause the crystal structure of the base metals to be coarsened. Whenstainless steel members are set as the base metals, the crystalcoarsening temperature thereof is set to 800° C., so that the meltingpoint of the brazing filler metal should be not higher than 800° C.(this condition is regarded as “Condition A”).

[0072] While the respective samples of Examples 1-1 to 1-12 satisfyCondition A, the samples of Comparative Examples 1-1 to 1-4 and 1-6 donot satisfy Condition A. Since Comparative Examples 1-1 to 1-4 and 1-6and Examples 1-1 to 1-12 have common ranges of respective compositionratios of Au, Ag, and Cu, it is difficult to specify Condition A basedonly on the respective composition ratios of Au, Ag, and Cu.

[0073] On the other hand, when the total composition ratio of theadditive element is no more than 1 wt. % and when it reaches 36 wt. % asin Comparative Examples 1-1 to 1-4, the melting points exceed 800° C.,so that the samples thereof do not satisfy Condition A. However, any ofsamples satisfying Condition A as shown in Example 1-1 to 1-12 has atotal composition ratio of the additive element which is in a range ofmore than 1 wt. % to less than 36 wt. %. Therefore, to satisfy ConditionA, the total composition ratio of the additive element needs to be in arange of more than 1 wt. % to less than 36 wt. %. In this point of view,it can be said, particularly on the basis of values shown in Examples1-1 to 1-12, that the total composition ratio of the additive element ispreferably in a range of about 2 to about 35 wt. %. Further, even if thetotal composition ratio of the additive element is within this range,when the composition ratio of Au reaches 80 wt. % as shown inComparative Example 16, the melting point exceeds 800° C., so that thesample does not satisfy Condition A. In contrast to this, when thecomposition ratio of Au is less than 80 wt. % as shown in Examples 1-1to 1-12, any of the samples satisfies Condition A. Accordingly, in orderto satisfy Condition A, the composition ratio of Au is only required tobe less than 80 wt. %, and is preferably not more than about 79 wt. %.

[0074] Secondly, to conform to the brazing filler metal as the object ofthe invention, each of the Au—Ag—Cu based brazing filler metals needs tohave an excellent corrosion resistance (this condition is regarded as“Condition B”). In the respective samples in Table 1 and Table 2, onlythe sample of Comparative Example 1-8 is insufficient and the othersamples are excellent in corrosion resistance. The sample shown inComparative Example 1-8 has a composition ratio of Ag at 42 wt. %, andany of the other samples has a composition ratio of Ag of less than 42wt. %. Accordingly, Condition B is satisfied when the composition ratioof Ag is less than 42 wt. %.

[0075] Thirdly, to conform to the brazing filler metal as the object ofthe invention, each of the Au—Ag—Cu based brazing filler metals needs tosecure a sufficient joining strength (this condition is regarded as“Condition C”). In Table 1 and Table 2, the samples satisfying both theaforementioned Conditions A and B have joining strengths of 590 MPa evenat the minimum, and any of them exhibited a value better than those ofthe conventional brazing filler metals (Comparative Examples 1-9 and1-10). Accordingly, any of the samples satisfying both theaforementioned Conditions A and B satisfies Condition C.

[0076] Further, in both cases where the composition ratio of Au is 34wt. % as shown in Comparative Example 1-5 and where the compositionratio of Ag is 5 wt. % as shown in Comparative Example 1-7, thewettability is insufficient against stainless steel. Therefore, evenwhen the aforementioned Conditions A and B are satisfied, it ispreferable that the composition ratio of Au is more than 34 wt. %, andthe composition ratio of Ag is more than 5 wt. %. Besides, even when thecomposition ratio of Ag is more than 5 wt. %, particularly when thecomposition ratio of Ag is in a range of about 6 to about 41 wt. %, thecolor of the brazing filler metal increases in grade of silver gray ofAg to be closer to the color of stainless steel. As a result, when thestainless steel members are joined together using the brazing fillermetal, a portion thereof joined by the brazing can be made lessconspicuous, so that the brazing filler metal is preferable to joinmembers of which decorativeness in external appearance is required (for,example, a later-described case).

[0077] In consideration that the samples of Examples 1-10 and 1-11 areparticularly excellent in wettability against stainless steel, it ispreferable that the samples have a composition ratio of Au and acomposition ratio of Ag satisfying the following conditions, in additionto the aforementioned conditions.

[0078] The composition ratio of Au is in a range of about 47 to about 64wt. %.

[0079] The composition ratio of Ag is in a range of about 6 to about 20wt. %.

[0080] When the composition ratio of Ag is in a range of 6 to about 20wt. %, a brazing filler metal was provided which has such a goodwettability against stainless steel to spread particularly extensivelyon the surface thereof.

[0081] As described in the foregoing, the Au—Ag—Cu based brazing fillermetal is suited for low temperature joining, provided that thecomposition ratio of the additive element and the composition ratio ofAu fall within the ranges satisfying Condition A, and the compositionratio of Ag falls within the range satisfying Condition B, and thus canjoin base metals without causing crystal structure thereof to becoarsened. In this case, the face condition of the stainless steelmembers, prior to joining, is maintained, so that the Au—Ag—Cu basedbrazing filler metal is more preferable than the conventional brazingfiller metals (nickel based brazing filler metal and silver basedbrazing filler metal). Further, excellent corrosion resistance issecured, and joining strength is better than those of the conventionalbrazing filler metals to provide sufficient joining strength.Consequently, when satisfying these conditions, the Au—Ag—Cu basedbrazing filler becomes a brazing filler metal satisfying all of threerequirements, that is, enabling low temperature joining and securingexcellent corrosion resistance and sufficient joining strength. Thisbrazing filler metal becomes a preferable brazing filler metal forfabricating a stainless steel member (for example, a later-describedcase 2) by brazing. Furthermore, provided that both Au and Ag satisfythe aforementioned conditions, this brazing filler metal becomes a morepreferable brazing filler metal having further improved wettabilityagainst stainless steel.

[0082] Next, the reason why the Au—Ag—Cu based brazing filler metalcomposed of those metal elements at respective specified ratios asdescribed above can conform to the brazing filler metal as the object ofthe invention is described in detail hereinafter with reference to phasediagrams of binary systems of alloys, shown in FIGS. 6 to 11,respectively. FIG. 6 is a phase diagram of a binary system of Ag—Au, thehorizontal axis thereof showing a composition ratio of Au to Ag whilethe vertical axis thereof showing a melting point, FIG. 7 a phasediagram of a binary system of Cu—Au, the horizontal axis thereof showinga composition ratio of Au to Cu while the vertical axis thereof showinga melting point, and FIG. 8 a phase diagram of a binary system of Ag—Cu,the horizontal axis thereof showing a composition ratio of Cu to Agwhile the vertical axis thereof showing a melting point. FIG. 9 is aphase diagram of a binary system of Au—Ge, the horizontal axis thereofshowing a composition ratio of Ge to Au while the vertical axis thereofshowing a melting point, FIG. 10 a phase diagram of a binary system ofAu—Si, the horizontal axis thereof showing a composition ratio of Si toAu while the vertical axis thereof showing a melting point, and FIG. 11a phase diagram of a binary system of Au—Sn, the horizontal axis thereofshowing a composition ratio of Sn to Au while the vertical axis thereofshowing a melting point. Detailed description on each of the phasediagrams is stated in detail, respectively, in Literature 1 given below.

[0083] Literature 1: “Binary Alloy Phase Diagrams”, Vol. 1, Vol. 2,American Society for Metals, Metals Park, Ohio 44073

[0084] As shown in FIG. 6, in the case of a Ag—Au alloy, its meltingpoint is gradually lowered from about 1064° C. according as thecomposition ratio of Au is decreased. Upon the composition ratio of Aureaching 0, the melting point reaches the lowest temperature of about961° C.

[0085] As shown in FIG. 7, in the case of a Cu—Au alloy, its meltingpoint is gradually lowered from about 1064° C. according as thecomposition ratio of Au is decreased. Upon the composition ratio of Aureaching about 80 wt. %, the melting point reaches the lowesttemperature of about 889° C. and then rises up to about 1084° C. uponthe composition ratio of Au reaching 0.

[0086] As shown in FIG. 8, in the case of a Ag—Cu alloy, its meltingpoint is gradually lowered from about 1084° C. according as thecomposition ratio of Cu is decreased. Upon the composition ratio of Cureaching about 28 wt. % (the composition ratio of Ag reaching about 72wt. %), the melting point reaches the lowest temperature of about 780°C. In this event, there occurs a eutectic composition of the Ag—Cu alloywith a melting point being drastically lowered. A state of such aeutectic composition is designated as a eutectic of Ag—Cu.

[0087] In the Au—Ag—Cu based brazing filler metal, the additive elementis added to Au, Ag, and Cu. Each element of the additive element has aeutectic point that when the composition ratio of the element to Aureaches a certain value, the melting point of an alloy formed with Au isdrastically lowered. This eutectic point is referred hereafter to as aeutectic of additive element (the additive element (for example, Ge)might form a eutectic composition with Ag).

[0088] The eutectic of additive element is described in detail, takingthree cases of Au—Ge, Au—Si, and Au—Sn as examples, with reference tothe phase diagrams of binary systems of alloys shown in FIGS. 9 to 11.

[0089] As shown in FIG. 9, in the case of a Au—Ge alloy, its meltingpoint is gradually lowered from about 938° C. according as thecomposition ratio of Ge is decreased. Upon the composition ratio of Gereaching about 12.5 wt. % (with the composition ratio of Au reachingabout 87.5 wt. %), the melting point reaches the lowest temperature ofabout 361° C. and then rises up to about 1064° C. The Au—Ge alloy formsa composition forming eutectic (eutectic composition) upon this statewhere the melting point is at the lowest. A state of such a eutecticcomposition is designated as a eutectic of Au—Ge.

[0090] As shown in FIG. 10, in the case of a Au—Si alloy, its meltingpoint is gradually lowered from about 1414° C. according as thecomposition ratio of Si is decreased. Upon the composition ratio of Sireaching about 3.2 wt. % (with the composition ratio of Au reachingabout 96.8 wt. %), the melting point reaches the lowest temperature ofabout 363° C. and then rises up to about 1064° C. The Au—Si alloy formsa eutectic composition upon this state where the melting point is at thelowest. A state of such a eutectic composition is designated as aeutectic of Au—Si.

[0091] As shown in FIG. 11, in the case of a Au—Sn alloy, its meltingpoint is gradually lowered from about 1064° C. according as thecomposition ratio of Sn is increased. Upon the composition ratio of Snreaching about 20 wt. % (with the composition ratio of Au reaching about80 wt. %), the melting point is lowered to about 278° C., then rises upto about 419° C., and is lowered again. The Au—Sn alloy forms a eutecticcomposition when the melting point is lowered to about 278° C. A stateof such a eutectic composition is designated as a eutectic of Au Sn.

[0092] As any of the three Au—Ge, Au—Si, and Au—Sn alloys forms aeutectic composition with its melting point being drastically lowered,each of the alloys of Au and the additive element has the property ofthe melting point thereof being drastically lowered due to the formationof the eutectic composition. In view of the above fact, it is reasonedthat the Au—Ag—Cu based brazing filler metal is able to conform to thebrazing filler metal as the object of the invention, in the case of aspecific composition wherein the above-described eutectic of Ag—Cu andthe eutectic of the additive element can be utilized. Each of Ag and Cuis, however, a metal having homogeneous solubility with Au and is ineffect substituted for Au. Therefore, addition of Ag and Cu at improperratios may result in deviation of the composition ratios of Au and theadditive element, respectively, from those required for the eutecticcomposition. As a result, a decrease in melting point due to theeutectic of the additive element is no longer expected and occurrence ofuniform solid solution becomes also difficult.

[0093] From the viewpoints described above, the respective compositionratios of Au, Ag, and Cu, and the additive element, composing theAu—Ag—Cu based brazing filler metal, have respective ranges required forobtaining the brazing filler metal as the object of the invention, andit is reasoned that the respective composition ratios fall within therespective ranges found from the results of the tests.

[0094] To sum up, the Au—Ag—Cu based brazing filler metal according tothe invention is turned into a brazing filler metal which is capable oflow temperature joining and is excellent both in joining strength andcorrosion resistance, utilizing the eutectic of Ag—Cu as well as theeutectic of Au and the additive element, provided that the samesatisfies all of the following conditions 1) to 3). In this case,coarsening of the crystal structure of stainless steel members being thebase metals is not caused but the surface condition thereof, prior tojoining, is maintained, so that the stainless steel members can bejoined together without loss of the decorativeness of the externalappearance.

[0095] Condition 1) The total composition ratio of at least one kind ofelement of the additive element is in a range of more than 1 wt. % toless than 36 wt. %.

[0096] Condition 2) The composition ratio of Au is less than 80 wt. %.

[0097] Condition 3) The composition ratio of Ag is less than 42 wt. %.

[0098] Further, the Au—Ag—Cu based brazing filler metal even with theabove composition is improved in wettability against stainless steel,provided that the same satisfies the following Condition 4).

[0099] Condition 4) The composition ratio of Au is more than 34 wt. %,and the composition ratio of Ag is more than 5 wt. %.

[0100] The Au—Ag—Cu based brazing filler metal has a color which isincreased in the degree of silver gray of Ag to be closer to the colorof stainless steel, provided that the same further satisfies thefollowing Condition 5) in addition to the above conditions.

[0101] Condition 5) The composition ratio of Ag is in a range of about 6to about 41 wt. %.

[0102] Furthermore, the Au—Ag—Cu based brazing filler metal can befurther improved in wettability against stainless steel, provided thatthe same satisfies the following Conditions 6) and 7).

[0103] Condition 6) The composition ratio of Au is in a range of about47 to about 64 wt. %.

[0104] Condition 7) The composition ratio of Ag is in a range of about 6to about 20 wt. %.

[0105] (Second Brazing Filler Metal)

[0106] Subsequently, a Au—Ag—Cu—Ge based brazing filler metal which is asecond brazing filler metal according to the invention is describedhereinafter. This brazing filler metal is composed of, as mainconstituents, four kinds of elements Au, Ag, Cu, and Ge, and is thusproduced by limiting the above-described additive element of the firstbrazing filler metal only to one kind of element Ge. This brazing fillermetal is different in element but is produced by the same method as thatof the first brazing filler metal.

[0107] Ten samples being Examples numbered from 2-1 to 2-10 and 7samples being Comparative Examples numbered from 2-1 to 2-7 shown inTable 4, 17 samples, in total, of different Au—Ag—Cu—Ge based brazingfiller metals, were prepared by varying a composition ratio (wt. %) ofeach of Au, Ag, Cu, and Ge as appropriate. To examine properties of therespective prepared samples, brazing was implemented using as the basemetals stainless steel members whose material is set to SUS316L. Therespective samples were examined on the two items, a) melting point andc) wettability against SUS316L. The four samples of Examples 2-8 and 2-9and Comparative Examples 2-6 and 2-7 were examined on the other fouritems, b) brazing temperature, d) crystal coarsening of SUS316L, e)joining strength, and f) corrosion resistance. The results thereof areshown in Table 5. It should be noted that the indication of “Example”and “Comparative Example” is the same as that of the first brazingfiller metal. The e) joining strength and f) corrosion resistance arechecked in the same manner as that of the first brazing filler metal.

[0108] As shown in Table 4, the melting points of the samples ofExamples 2-1 to 2-10 are 780° C. (Example 2-4) even at the maximum, andthe melting point of any of the samples is thus not higher than 800° C.The melting points of the samples of Comparative Examples 2-1 to 2-3,however, exceed 800° C. Regarding the wettability against SUS316L, whileall of the samples of Examples 2-1 to 2-10 provided excellent results,the samples of Comparative Examples 2-1 to 2-5 and Comparative Example2-7 other than Comparative Example 2-6 provided just slightly goodresults which were not sufficient. Besides, as shown in Table 5, whilethe brazing temperature for the sample of Comparative Example 2-7exceeded 800° C., that for any of the other samples was lower than 800°C. Crystal coarsening of SUS316L occurred in the sample of ComparativeExample 2-7, and not in the other samples. The joining strengths of thesamples were 840 MPa even at the minimum, and any of them was betterthan those of the conventional brazing filler metals. Regarding thecorrosion resistance, any of the samples other than Comparative Example2-6 exhibited an excellent result.

[0109] The Au—Ag—Cu—Ge based brazing filler metal also needs to satisfy,similarly to the first brazing filler metal, the above-described threeconditions A, B and C, and, from the results shown in Tables 4 and 5,the conditions for satisfaction are as follows:

[0110] Condition A)

[0111] Since Comparative Examples 2-1 to 2-3 and Examples 2-1 to 2-10have common ranges of respective composition ratios of Ag and Cu, it isdifficult to specify Condition A based only on the respectivecomposition ratios of Ag and Cu.

[0112] Next, when the composition ratio of Ge is no more than 4 wt. %and when it reaches 24 wt. % as shown in Comparative Examples 2-1 to2-3, the melting points exceed 800° C., so that the samples thereof donot satisfy Condition A. However, any of samples satisfying Condition Aas shown in Example 2-1 to 2-10 has a composition ratio of Ge which isin a range of more than 4 wt. % to less than 24 wt. %. Therefore, tosatisfy Condition A, the composition ratio of Ge needs to be in a rangeof more than 4 wt. % to less than 24 wt. %. In this point of view, itcan be said, particularly on the basis of values shown in Examples 2-1to 2-10, that the composition ratio of Ge is preferably in a range ofabout 5 to about 23 wt. %. However, even if the composition ratio of Geis within this range, when the composition ratio of Au reaches 34 wt. %as shown in Comparative Example 2-3, the melting point exceeds 800° C.,so that the sample does not satisfy Condition A. In contrast to this,when the composition ratio of Au is more than 34 wt. % as shown inExamples 2-1 to 2-10, the melting points become lower than 800° C., andthus the samples satisfy Condition A. Accordingly, in order to satisfyCondition A, the composition ratio of Au is only required to be morethan 34 wt. %, and is preferably not less than about 35 wt. %.

[0113] Condition B)

[0114] Only the sample of Comparative Example 2-6 is insufficient andthe other samples are excellent in corrosion resistance. The sampleshown in Comparative Example 2-6 has a composition ratio of Ag at 41 wt.%, and the other samples have composition ratios of Ag at less than 41wt. %. Accordingly, Condition B is satisfied when the composition ratioof Ag is less than 41 wt. %.

[0115] Condition C)

[0116] The samples satisfying both the aforementioned Conditions A and Bhave joining strengths of 880 MPa even at the minimum, and any of themexhibited a value better than those of the conventional brazing fillermetals. Accordingly, the samples satisfying both the aforementionedConditions A and B satisfy Condition C.

[0117] Further, even the samples satisfying Conditions A and B areparticularly improved in wettability against stainless steel, providedthat the same satisfy all of the following conditions as in Examples 2-4to 2-10.

[0118] The composition ratio of Au is in a range of about 35 to about 80wt. %.

[0119] The composition ratio of Ag is in a range of about 5 to about 40wt. %.

[0120] The composition ratio of Ge is in a range of about 10 to about 19wt. %.

[0121] Particularly when the composition ratio of Ag is in a range ofabout 6 to about 40 wt. %, the color of the brazing filler metal becomescloser to silver gray, so that a portion of stainless steel membersjoined by the brazing can be made less conspicuous.

[0122] As described in the foregoing, the Au—Ag—Cu—Ge based brazingfiller metal becomes a brazing filler metal satisfying all of the threerequirements, that is, enabling low temperature joining and securingexcellent corrosion resistance and sufficient joining strength, providedthat the composition ratios of Ge and Au respectively fall within theaforementioned ranges satisfying Condition A, and the composition ratioof Ag falls within the aforementioned range satisfying Condition B.Furthermore, provided that the composition ratios of Au, Ag, and Ge arerespectively within the above-described ranges for excellent wettabilityagainst stainless steel, the Au—Ag—Cu—Ge based brazing filler metal isimproved in wettability against stainless steel. In this case, thebrazing filler metal spreads extensively on the surfaces of thestainless steel members, thus facilitating the joining work, and, as aresult, the brazing filler metal becomes more preferable.

[0123] Next, the reason why the Au—Ag—Cu—Ge based brazing filler metalcomposed of those metal elements at respective specified ratios asdescribed above can conform to the brazing filler metal as the object ofthe invention is described in detail hereinafter with reference to phasediagrams of binary systems of alloys, shown in FIGS. 12 and 13,respectively with the above-described FIGS. 8 and 9.

[0124]FIG. 12 is a phase diagram of a binary system of Ag—Ge, thehorizontal axis thereof showing a composition ratio of Ag to Ge whilethe vertical axis thereof showing a melting point, FIG. 13 a phasediagram of a binary system of Cu—Ge, the horizontal axis thereof showinga composition ratio of Cu to Ge while the vertical axis thereof showinga melting point, and detailed description on each of the phase diagramsis stated, respectively, in the foregoing Literature 1.

[0125] As shown in FIG. 12, in the case of a Ag—Ge alloy, its meltingpoint is gradually lowered from about 938° C. according as thecomposition ratio of Ag is increased. Upon the composition ratio of Agreaching about 84 wt. % (the composition ratio of Ge reaching about 16wt. %), the melting point reaches the lowest temperature of about 651°C., and then rises up to about 961° C. While there occurs a eutecticcomposition of the Ag—Ge alloy, its melting point is drasticallylowered. A state of such a eutectic composition is designated as aeutectic of Ag—Ge.

[0126] As shown in FIG. 13, in the case of a Cu—Ge alloy, its meltingpoint is gradually lowered from about 938° C. according as thecomposition ratio of Cu is increased. Upon the composition ratio of Cureaching about 60.4 wt. % (the composition ratio of Ge reaching about39.6 wt. %), the melting point reaches the lowest temperature of about644° C., and then rises up to about 1084° C. upon the composition ratioof Cu reaching 100. There occurs a eutectic composition of the Cu—Gealloy upon this state where the melting point is at the lowest. A stateof such a eutectic composition is designated as a eutectic of Cu—Ge.

[0127] Since the second brazing filler metal is produced by adding Ge toAu—Ag—Cu, there is a conceivable composition utilizing the eutectic ofAg—Cu, similarly to the first brazing filler metal. Further, as shown inFIGS. 9, 12 and 13, when the composition ratio of Ge to Au, Ag, and Cureaches certain values, Ge forms eutectics with Au, Ag, and Cu. Besides,when there occur eutectic compositions of the Au—Ge alloy, the Ag—Gealloy, and the Cu—Ge alloy in which they respectively form the eutecticof Au—Ge, the eutectic of Ag—Ge, and the eutectic of Cu—Ge as describedabove, their melting points are lowered. However, since each of Ag andCu to be added is in effect substituted for Au, addition of Ag and Cu inimproper amounts may result in deviation from those required for theeutectic compositions. It is reasoned that when the second brazingfiller metal has a specific composition utilizing any of the eutectic ofAu—Ge, the eutectic of Ag—Ge, the eutectic of Cu—Ge, its melting pointis lowered, and when it has a specific composition utilizing all ofthem, the melting point is further lowered. Therefore, the respectivecomposition ratios of Au, Ag, Cu, and Ge, composing the Au—Ag—Cu—Gebased brazing filler metal, have respective ranges required forobtaining the brazing filler metal as the object of the invention, andit is reasoned that the respective composition ratios fall within therespective ranges found from the results of the tests shown in Tables 4and 5 described above.

[0128] To sum up, the Au—Ag—Cu—Ge based brazing filler metal accordingto the invention is turned into a brazing filler metal which is capableof low temperature joining and is excellent both in joining strength andcorrosion resistance, utilizing four eutectics, that is, the eutectic ofAg—Cu, the eutectic of Au—Ge, the eutectic of Ag—Ge, and the eutectic ofCu—Ge, provided that the same satisfies all of the following conditions8) to 10).

[0129] Condition 8) The composition ratio of Ge is in a range of morethan 4 wt. % to less than 24 wt. %.

[0130] Condition 9) The composition ratio of Au is more than 34 wt. %.

[0131] Condition 10) The composition ratio of Ag is less than 41 wt. %.

[0132] Furthermore, the Au—Ag—Cu—Ge based brazing filler metal even withthe above composition can be further improved in wettability againststainless steel, provided that the same satisfies all of the followingconditions 11) to 13).

[0133] Condition 11) The composition ratio of Au is in a range of about35 to about 80 wt. %.

[0134] Condition 12) The composition ratio of Ag is in a range of about5 to about 40 wt. %.

[0135] Condition 13) The composition ratio of Ge is in a range of about10 wt. to about 19 wt. %.

[0136] (Third Brazing Filler Metal)

[0137] Subsequently, a Au—Ag—Cu—Si based brazing filler metal which is athird brazing filler metal according to the invention is describedhereinafter. This brazing filler metal is composed of, as mainconstituents, four kinds of elements Au, Ag, Cu, and Si, and is thusproduced by limiting the above-described additive element of the firstbrazing filler metal only to one kind of element Si. This brazing fillermetal is different in element but is produced by the same method as thatof the first brazing filler metal.

[0138] Eleven samples being Examples numbered from 3-1 to 3-11 and 6samples being Comparative Examples numbered from 3-1 to 3-6 shown inTable 6, 17 samples, in total, of different Au—Ag—Cu—Si based brazingfiller metals, were prepared by varying a composition ratio (wt. %) ofeach of Au, Ag, Cu, and Si as appropriate. To examine properties of therespective prepared samples, brazing was implemented using as the basemetals stainless steel members whose material is set to SUS316L. Therespective samples were examined, similarly to the second brazing fillermetal, on the two items, a) melting point and c) wettability againstSUS316L. The four samples of Examples 3-9 and 310 and ComparativeExamples 3-5 and 3-6 were examined on the other four items. The resultsthereof are as shown in Table 7. It should be noted that the indicationof “Example” and “Comparative Example” is the same as that of the firstbrazing filler metal. The e) joining strength and f) corrosionresistance are checked in the same manner as that of the first brazingfiller metal.

[0139] As shown in Table 6, the melting points of the samples ofExamples 3-1 to 3-11 are 782° C. (Example 3-1) even at the maximum, andthe melting point of any of the samples is thus not higher than 800° C.The melting points of the samples of Comparative Examples 3-1 to 3-3 and3-5, however, exceed 800° C. Regarding the wettability against SUS316L,while all of the samples of Examples 3-1 to 3-11 provided excellentresults, the samples of Comparative Examples 3-2 to 3-5 other thanComparative Examples 3-1 and 3-6 provided just slightly good resultswhich were not sufficient. Besides, as shown in Table 7, while thebrazing temperature for the sample of Comparative Example 3-5 exceeded800° C., that for any of the other samples was lower than 800° C.Crystal coarsening of SUS316L occurred in the sample of ComparativeExample 3-5, and not in the other samples. The joining strengths of thesamples were 770 MPa even at the minimum, and any of them was betterthan those of the conventional brazing filler metals. Regarding thecorrosion resistance, any of the samples other than Comparative Example3-6 exhibited an excellent result.

[0140] The Au—Ag—Cu—Si based brazing filler metal also needs to satisfy,similarly to the first brazing filler metal, the above-described threeconditions A, B and C, and, from the results shown in Tables 6 and 7,the conditions for satisfaction are as follows:

[0141] Condition A)

[0142] Since Comparative Examples 3-1 to 3-3 and 3-5 and Examples 3-1 to3-11 have common ranges of respective composition ratios of Au, Ag andCu, it is difficult to specify Condition A based only on the respectivecomposition ratios of Au, Ag and Cu.

[0143] Next, when the composition ratio of Si is no more than 0.9 wt. %and when it reaches 19 wt. % as shown in Comparative Examples 3-1 to3-3, the melting points exceed 800° C., so that the samples thereof donot satisfy Condition A. However, any of samples satisfying Condition Aas shown in Example 3-1 to 3-11 has a composition ratio of Si which isin a range of more than 0.9 wt. % to less than 19 wt. %. Therefore, tosatisfy Condition A, the composition ratio of Si needs to be in a rangeof more than 0.9 wt. % to less than 19 wt. %. In this point of view, itcan be said, particularly on the basis of values shown in Examples 3-1to 3-11, that the composition ratio of Si is preferably in a range ofabout 1 to about 18 wt. %. However, even if the composition ratio of Siis limited to this range, when the composition ratio of Au reaches 40wt. % as shown in Comparative Example 3-3, the melting point exceeds800° C., so that the sample does not satisfy Condition A. In contrast tothis, when the composition ratio of Au is more than 40 wt. % as shown inExamples 3-1 to 3-11, the melting points become lower than 800° C., andthus the samples satisfy Condition A. Accordingly, in order to satisfyCondition A, the composition ratio of Au needs to be more than 40 wt. %.Further, even if the composition ratio of Au is limited to this range,when the composition ratio of Ag reaches 4 wt. % as shown in ComparativeExample 3-5, the melting point exceeds 800° C., so that the sample doesnot satisfy Condition A. In contrast to this, when the composition ratioof Ag is more than 4 wt. % as shown in Examples 3-1 to 3-11, the meltingpoints become lower than 800° C., and thus the samples satisfy ConditionA. Accordingly, in order to satisfy Condition A, the composition ratioof Ag is only required to be more than 4 wt. %, and is preferably notless than about 5 wt. %.

[0144] Condition B)

[0145] Only the sample of Comparative Example 3-6 is insufficient andthe other samples are excellent in corrosion resistance. The sampleshown in Comparative Example 3-6 has a composition ratio of Ag at 37 wt.%, and the other samples have composition ratios of Ag at less than 37wt. %. Accordingly, Condition B is satisfied when the composition ratioof Ag is less than 37 wt. %.

[0146] Condition C)

[0147] The samples satisfying both the aforementioned Conditions A and Bhave joining strengths of 770 MPa even at the minimum, and any of themexhibited a value better than those of the conventional brazing fillermetals. Accordingly, the samples satisfying both the aforementionedConditions A and B satisfy Condition C.

[0148] Further, even the samples satisfying Conditions A and B areparticularly improved in wettability against stainless steel, providedthat the same satisfy all of the following conditions as in Examples 3-5to 3-11.

[0149] The composition ratio of Au is in a range of about 41 to about 79wt. %.

[0150] The composition ratio of Ag is in a range of about 5 to about 36wt. %.

[0151] As described in the foregoing, the Au—Ag—Cu—Si based brazingfiller metal becomes a brazing filler metal satisfying all of the threerequirements, that is, enabling low temperature joining and securingexcellent corrosion resistance and sufficient joining strength, providedthat the composition ratios of Si, Au, and Ag respectively fall withinthe aforementioned ranges satisfying Condition A, and the compositionratio of Ag falls within the aforementioned range satisfying ConditionB. Furthermore, provided that the composition ratios of Au and Ag arerespectively within the above-described ranges for excellent wettabilityagainst stainless steel, the Au—Ag—Cu—Si based brazing filler metal isimproved in wettability against stainless steel. In this case, thebrazing filler metal spreads extensively on the surfaces of thestainless steel members, thus facilitating the joining work, and, as aresult, the brazing filler metal becomes more preferable.

[0152] Next, the reason why the Au—Ag—Cu—Si based brazing filler metalcomposed of those metal elements at respective specified ratios asdescribed above can conform to the brazing filler metal as the object ofthe invention is described in detail hereinafter with reference to aphase diagram of a binary system of an alloy shown in FIG. 14 with theabove-described FIGS. 8 and 10.

[0153]FIG. 14 is a phase diagram of a binary system of Si—Ag, thehorizontal axis thereof showing a composition ratio of Ag to Si whilethe vertical axis thereof showing a melting point, and detaileddescription on the phase diagram is stated in the foregoing Literature1.

[0154] In the case of a Ag—Si alloy, its melting point is graduallylowered from about 1414° C. according as the composition ratio of Ag isincreased. Upon the composition ratio of Ag reaching about 97 wt. % (thecomposition ratio of Si reaching about 3 wt. %), the melting pointreaches the lowest temperature of about 845° C., and then rises up toabout 961° C. When there occurs a eutectic composition of the Ag—Sialloy, its melting point is drastically lowered. A state of such aeutectic composition is designated as a eutectic of Ag—Si.

[0155] Since the third brazing filler metal is produced by adding Si toAu—Ag—Cu, there is a conceivable composition utilizing a eutectic ofAg—Cu, similarly to the first brazing filler metal. Further, as shown inFIGS. 10 and 14, when the composition ratio of Si to Au or Ag reaches acertain value, Si forms a eutectic with Au or Ag. Besides, when thereoccur eutectic compositions of the Au—Si alloy and the Ag—Si alloy inwhich they respectively form the eutectic of Au Si and the eutectic ofAg—Si as described above, their melting points are lowered. However,addition of Ag and Cu in improper amounts may result in deviation fromthose required for the eutectic compositions. Therefore, the respectivecomposition ratios of Au, Ag, Cu, and Si, composing the Au—Ag—Cu—Sibased brazing filler metal, have respective ranges required forobtaining the brazing filler metal as the object of the invention, andit is reasoned that the respective composition ratios fall within therespective ranges found from the results of the tests shown in Tables 6and 7 described above.

[0156] To sum up, the Au—Ag—Cu—Si based brazing filler metal accordingto the invention is turned into a brazing filler metal which is capableof low temperature joining and is excellent both in joining strength andcorrosion resistance, utilizing three eutectics, that is, the eutecticof Ag—Cu, the eutectic of Au—Si, and the eutectic of Ag—Si, providedthat the same satisfies all of the following conditions 14) to 16).

[0157] Condition 14) The composition ratio of Si is in a range of morethan 0.9 wt. % to less than 19 wt. %.

[0158] Condition 15) The composition ratio of Au is more than 40 wt. %.

[0159] Condition 16) The composition ratio of Ag is in a range of morethan 4 wt. % to less than 37 wt. %.

[0160] Further, the Au—Ag—Cu—Si based brazing filler metal even with theabove composition can be further improved in wettability againststainless steel, provided that the same satisfies both the followingconditions 17) and 18).

[0161] Condition 17) The composition ratio of Au is in a range of about41 to about 79 wt. %.

[0162] Condition 18) The composition ratio of Ag is in a range of about5 to about 36 wt. %.

[0163] (Fourth Brazing Filler Metal)

[0164] Subsequently, a Au—Ag—Cu—Ge—Si—Sn based brazing filler metalwhich is a fourth brazing filler metal according to the invention isdescribed hereinafter. This brazing filler metal is composed of, as mainconstituents, Au, metals having homogeneous solubility with Au, and atleast one kind of element out of Ge, Si, and Sn, and is thus produced bylimiting the additive element of the above-described first brazingfiller metal to the three kinds of elements Ge, Si, and Sn. As themetals having homogeneous solubility with Au, Ag and Cu are used here;It should be noted that this brazing filler metal is different inelement but is produced by the same method as that of the first brazingfiller metal.

[0165] Twenty-eight samples being Examples numbered from 4-1 to 4-28 and11 samples being Comparative Examples numbered from 4-1 to 4-11 shown inTables 8 and 9, 39 samples, in total, of different Au—Ag—Cu—Ge—Si—Snbased brazing filler metals, were prepared by varying six kinds ofelements Au, Ag, Cu, Ge, Si, and Sn and a composition ratio (wt. %) ofeach of them as appropriate. The respective prepared samples wereexamined in properties on the selected six items which are the same asthose of the first brazing filler metal. It should be noted that theindication of “Example” and “Comparative Example” is the same as that ofthe first brazing filler metal. The e) joining strength and f) corrosionresistance are checked in the same manner as that of the first brazingfiller metal.

[0166] As shown in Tables 8 and 9, the melting points of the samples ofExamples 4-1 to 4-28 are 743° C. (Example 4-5) even at the maximum, andthe melting point of any of the samples is thus not higher than 800° C.The melting points of the samples of Comparative Examples 4-1 to 4-7 and4-9, however, exceed 800° C. Regarding the wettability against SUS316L,while all of the samples of Examples 4-1 to 4-28 provided excellentresults, any of the samples of Comparative Examples other thanComparative Example 4-11 provided a just slightly good result which wasnot sufficient. Besides, the brazing temperature for any of the samplesof Examples 4-1 to 4-28 was lower than 800° C. Crystal coarsening ofSUS316L occurred in the sample of Comparative Examples 4-1 to 4-7 and4-9, and not in the other samples. The joining strengths of the sampleswere 600 MPa even at the minimum, and any of them was better than thoseof the conventional brazing filler metals. Regarding the corrosionresistance, any of the samples other than Comparative Example 4-11exhibited an excellent result.

[0167] The Au—Ag—Cu—Ge—Si—Sn based brazing filler metal also needs tosatisfy, similarly to the first brazing filler metal, theabove-described three conditions A, B and C, and, from the results shownin Tables 8 and 9, the conditions for satisfaction are as follows:

[0168] Condition A)

[0169] Since Comparative Examples 4-1 to 4-7 and 4-9 and Examples 4-1 to428 have common ranges of respective composition ratios of Au, Ag andCu, it is difficult to specify Condition A based only on the respectivecomposition ratios of Au, Ag, and Cu.

[0170] Next, when the total composition ratio of Ge, Si, and Sn is nomore than 1 wt. % and when it reaches 35 wt. % as shown in ComparativeExamples 4-1 to 4-7, the melting points exceed 800° C., so that samplesthereof do not satisfy Condition A. However, any of samples satisfyingCondition A as shown in Example 4-1 to 4-28 has a total compositionratio of Ge, Si, and Sn which is in a range of more than 1 wt. % to lessthan 35 wt. %. Therefore, to satisfy Condition A, the total compositionratio of Ge, Si, and Sn needs to be in a range of more than 1 wt. % toless than 35 wt. %. In this point of view, it can be said, particularlyon the basis of values shown in Examples 4-1 to 4-28, that the totalcomposition ratio of Ge, Si, and Sn is preferably in a range of about 2to about 34 wt. %. Further, even if the total composition ratio of Ge,Si, and Sn is within this range, when the composition ratio of Aureaches 80 wt. % as shown in Comparative Example 4-9, the melting pointexceeds 800° C., so that the sample does not satisfy Condition A. Incontrast to this, when the composition ratio of Au is less than 80 wt. %as shown in Examples 4-1 to 4-28, any of the samples satisfies ConditionA. Accordingly, in order to satisfy Condition A, the composition ratioof Au is only required to be less than 80 wt. %, and is preferably notmore than about 79 wt. %.

[0171] Condition B)

[0172] Only the sample of Comparative Example 4-11 is insufficient andthe other samples are excellent in corrosion resistance. The sampleshown in Comparative Example 4-11 has a composition ratio of Ag at 42wt. %, and any of the other samples has a composition ratio of Ag atless than 42 wt. %. Accordingly, Condition B is satisfied when thecomposition ratio of Ag is less than 42 wt. %.

[0173] Condition C)

[0174] The samples satisfying both the aforementioned Conditions A and Bhave joining strengths of 600 MPa even at the minimum, and any of themexhibited a value better than those of the conventional brazing fillermetals. Accordingly, the samples satisfying both the aforementionedConditions A and B satisfy Condition C.

[0175] Further, even the samples satisfying the aforementionedConditions A and B are insufficient in wettability against stainlesssteel, in both cases where the composition ratio of Au is 34 wt. % asshown in Comparative Example 4-8 and where the composition ratio of Agis 5 wt. % as shown in Comparative Example 4-10. Therefore, even whenthe aforementioned Conditions A and B are satisfied, it is preferablethat the composition ratio of Au is more than 34 wt. %, and thecomposition ratio of Ag is more than 5 wt. %. Even when the compositionratio of Ag is more than 5 wt. %, particularly when the compositionratio of Ag is in a range of about 6 to about 41 wt. %, the color of thebrazing filler metal increases in grade of silver gray of Ag to becloser to the color of stainless steel.

[0176] In consideration that the samples of Examples 4-26 and 4-27 areparticularly excellent in wettability against stainless steel, it ispreferable that the samples have a composition ratio of Au and acomposition ratio of Ag satisfying the following conditions, in additionto the aforementioned conditions.

[0177] The composition ratio of Au is in a range of about 47 to about 64wt. %

[0178] The composition ratio of Ag is in a range of about 6 to about 20wt. %.

[0179] As described in the foregoing, the Au—Ag—Cu—Ge—Si—Sn basedbrazing filler metal becomes a brazing filler metal satisfying all ofthe three requirements, that is, enabling low temperature joining andsecuring excellent corrosion resistance and sufficient joining strength,provided that the total composition ratio of Ge, Si, and Sn and thecomposition ratio of Au respectively fall within the ranges satisfyingCondition A and the composition ratio of Ag falls within the rangesatisfying Condition B. Furthermore, provided that the compositionratios of Au and Ag are respectively within the above-described rangesfor excellent wettability against stainless steel, the Au—Ag—Cu—Ge—Si—Snbased brazing filler metal is improved in wettability against stainlesssteel.

[0180] Next, the reason why the Au—Ag—Cu—Ge—Si—Sn based brazing fillermetal composed of those metal elements at respective specified ratios asdescribed above can conform to the brazing filler metal as the object ofthe invention is described in detail hereinafter with reference to aphase diagram of a binary system of an alloy shown in FIG. 15 with theabove-described FIGS. 8 to 14.

[0181]FIG. 15 is a phase diagram of a binary system of Sn—Ag, thehorizontal axis thereof showing a composition ratio of Sn to Ag whilethe vertical axis thereof showing a melting point, and detaileddescription on the phase diagram is stated in the foregoing Literature1.

[0182] In the case of a Ag—Sn alloy, its melting point is graduallylowered from about 981° C. according as the composition ratio of Sn isincreased. Upon the composition ratio of Sn reaching about 96.5 wt. %(the composition ratio of Ag reaching about 3.5 wt. %), the meltingpoint reaches the lowest temperature of about 221° C., and then rises upto about 231° C. When there occurs a eutectic composition of the Ag—Snalloy, its melting point is lowered. A state of such a eutecticcomposition is designated as a eutectic of Ag—Sn.

[0183] Since the fourth brazing filler metal is produced by adding Ge,Si, and Sn to Au—Ag—Cu, there is a conceivable composition utilizing aeutectic of Ag—Cu, a eutectic of Au—Ge, a eutectic of Ag—Ge, and aeutectic of Cu—Ge, similarly to the second brazing filler metal.Further, when the composition ratio of Au to Si and Sn reaches certainvalues, Au forms eutectics with Si and Sn, so that there is also aconceivable composition utilizing a eutectic of Au—Si and a eutectic ofAu—Sn. Further, since Ag also forms eutectics with Si and Sn when thecomposition ratio of Ag to Si and Sn reaches certain values, there isalso a conceivable composition utilizing a eutectic of Ag—Si and aeutectic of Ag—Sn. From the above viewpoint, the melting point islowered when the fourth brazing filler metal has a composition utilizingany of eight eutectics, that is, the eutectic of Ag—Cu, the eutectic ofAu—Ge, the eutectic of Ag—Ge, the eutectic of Cu Ge, the eutectic ofAu—Si, the eutectic of Au—Sn, the eutectic of Ag—Si, and the eutectic ofAg—Sn. However, since each of Ag and Cu to be added is in effectsubstituted for Au, addition of Ag and Cu in improper amounts may resultin deviation from those required for the eutectic compositions.Therefore, the respective composition ratios of Au, Ag, Cu, Ge, Si andSn, composing the Au—Ag—Cu—Ge—Si—Sn based brazing filler metal, haverespective ranges required for obtaining the brazing filler metal as theobject of the invention, and it is reasoned that the respectivecomposition ratios fall within the ranges found from the results of thetests shown in Tables 8 and 9 described above.

[0184] To sum up, the Au—Ag—Cu—Ge—Si—Sn based brazing filler metalaccording to the invention is turned into a brazing filler metal whichis capable of low temperature joining and is excellent both in joiningstrength and corrosion resistance, utilizing eight eutectics, that is,the eutectic of Ag—Cu, the eutectic of Au—Ge, the eutectic of Ag—Ge, theeutectic of Cu—Ge, the eutectic of Au—Si, the eutectic of Au—Sn, theeutectic of Ag—Si, and the eutectic of Ag—Sn, provided that the samesatisfies all of the following conditions 19) to 21).

[0185] Condition 19) The total composition ratio of Ge, Si, and Sn is ina range of more than 1 wt. % to less than 35 wt. %.

[0186] Condition 20) The composition ratio of Au is less than 80 wt. %.

[0187] Condition 21) The composition ratio of Ag is less than 42 wt. %.

[0188] Further, the Au—Ag—Cu—Ge—Si—Sn based brazing filler metal becomesa more preferable brazing filler metal having improved wettabilityagainst stainless steel, provided that the same satisfies both thefollowing conditions 22) and 23).

[0189] Condition 22) The composition ratio of Au is in a range of about47 to about 64 wt. %.

[0190] Condition 23) The composition ratio of Ag is in a range of about6 to about 20 wt. %.

[0191] (Fifth Brazing Filler Metal)

[0192] Subsequently, a Au—Ag—Cu—Pd based brazing filler metal which is afifth brazing filler metal according to the invention is describedhereinafter. This brazing filler metal is composed of, as mainconstituents, four kinds of elements Au, Ag, Cu, and palladium (Pd)having homogeneous solubility with Au, Ag, and Cu added thereto, and afirst additive element added to the main constituents. The firstadditive element is composed of elements of metal or semiconductor,similarly to the first brazing filler metal, and is at least one kind ofelement out of Al, Bi, Ga, Ge, In, Sb, Si, Sn, Pb, Te, and Tl. ThisAu—Ag—Cu—Pd based brazing filler metal is different in element but isproduced by the same method as that of the first brazing filler metal.

[0193] Thirteen samples being Examples numbered from 5-1 to 5-13 shownin Table 10 and 9 samples being Comparative Examples numbered from 5-1to 5-9 shown in Table 11, 22 samples, in total, of different Au—Ag—Cu—Pdbased brazing filler metals, were prepared by varying a compositionratio (wt. %) of each of Au, Ag, Cu, and Pd as appropriate as well asvarying the kind and a composition ratio (wt. %) of each of the elementsconstituting the first additive element as appropriate. In this event,the samples were prepared using one kind of element out of Ga, Al, andBi and using two or more kinds of elements out of them as the firstadditive element. The two or more kinds of elements of the firstadditive element are as follows:

[0194] Bi and Si (Example 5-2); In, Ga, and Te (Example 5-3)

[0195] Al, Ge, and Tl (Example 5-4); Pb and Sn (Example 5-5)

[0196] Sb, Ge, and Te (Example 5-6)

[0197] Sn and Bi (Example 5-7, Comparative Example 5-5)

[0198] Al and Ge (Example 5-8); Ge and Ga (Example 5-9, ComparativeExample 5-6)

[0199] Sn and Sb (Example 5-10, Comparative Example 5-7)

[0200] Ge and Pb (Example 5-11)

[0201] In and Sn (Example 5-12, Comparative Example 5-8)

[0202] In and Ti (Example 5-13, Comparative Example 5-9)

[0203] Ga, Si, and Te (Comparative Example 5-3); Te, Ga and Pb(Comparative Example 5-4)

[0204] The respective prepared samples were examined in properties onthe selected six items which are the same as those of the first brazingfiller metal. It should be noted that the indication of “Example” and“Comparative Example” is the same as that of the first brazing fillermetal. The e) joining strength and f) corrosion resistance are checkedin the same manner as that of the first brazing filler metal.

[0205] As shown in Tables 10 and 11, the melting points of the samplesof Examples 5-1 to 5-13 are 724° C. (Example 5-9) even at the maximum,and the melting point of any of the samples is thus not higher than 800°C. The melting points of the samples of Comparative Examples 5-1 to 5-4,5-6, and 5-9, however, exceed 800° C. Regarding the wettability againstSUS316L, while the samples of Examples 5-1 to 5-13 provided excellentresults, any of the samples of Comparative Examples 5-1 to 5-9 otherthan Comparative Example 5-8 provided a just slightly good result whichwas not sufficient. Besides, the brazing temperature for any of thesamples of Examples 5-1 to 5-13 was lower than 800° C. Crystalcoarsening of SUS316L occurred in the samples of Comparative Examples5-1 to 5-4, 5-6, and 5-9, and not in the other samples. The joiningstrengths of the samples were 590 MPa even at the minimum, and any ofthem was better than those of the conventional brazing filler metals.Regarding the corrosion resistance, any of the samples other thanComparative Example 5-8 exhibited an excellent result.

[0206] The Au—Ag—Cu—Pd based brazing filler metal also needs to satisfy,similarly to the first brazing filler metal, the above-described threeconditions A, B and C, and, from the results shown in Tables 10 and 11,the conditions for satisfaction are as follows:

[0207] Condition A)

[0208] Since Comparative Examples 5-1 to 5-4, 5-6, and 5-9 and Examples5-1 to 5-13 have common ranges of respective composition ratios of Au,Ag, and Cu, it is difficult to specify Condition A based only on therespective composition ratios of Au, Ag, and Cu.

[0209] Next, when the total composition ratio of the first additiveelement is no more than 1 wt. % and when it reaches 38 wt. % as shown inComparative Examples 5-1 to 5-4, the melting points exceed 800° C., sothat samples thereof do not satisfy Condition A. However, any of samplessatisfying Condition A as shown in Example 5-1 to 5-13 has a totalcomposition ratio of the first additive element which is in a range ofmore than 1 wt. % to less than 38 wt. %. Therefore, to satisfy ConditionA, the total composition ratio of the first additive element needs to bein a range of more than 1 wt. % to less than 38 wt. %. In this point ofview, it can be said, particularly on the basis of values shown inExamples 5-1 to 5-13, that the total composition ratio of the firstadditive element is preferably in a range of about 2 to about 37 wt. %.However, even if the total composition ratio of the first additiveelement is within this range, when the composition ratio of Au reaches82 wt. % as shown in Comparative Example 5-6, the melting point exceeds800° C., so that the sample does not satisfy Condition A. In contrast tothis, when the composition ratio of Au is less than 82 wt. % as shown inExamples 5-1 to 5-13, any of the samples satisfies Condition A.Accordingly, in order to satisfy Condition A, the composition ratio ofAu is only required to be less than 82 wt. %. Further, even if thecomposition ratio of Au is within this range, when the composition ratioof Pd is 34 wt. % as shown in Comparative Example 5-9, the melting pointexceeds 800° C., so that the sample does not satisfy Condition A.However, if the composition ratio of Pd is less than 34 wt. %, any ofthe samples satisfies Condition A. Accordingly, in order to satisfyCondition A, the composition ratio of Pd is only required to be lessthan 34 wt. %, and is preferably not more than about 33 wt. %.

[0210] Condition B)

[0211] Only the sample of Comparative Example 5-8 is insufficient andthe other samples are excellent in corrosion resistance. The sampleshown in Comparative Example 5-8 has a composition ratio of Ag at 47 wt.%, and any of the other samples has a composition ratio of Ag at lessthan 47 wt. %. Accordingly, Condition B is satisfied when thecomposition ratio of Ag is less than 47 wt. %.

[0212] Condition C)

[0213] The samples satisfying both the aforementioned Conditions A and Bhave joining strengths of 590 MPa even at the minimum, and any of themexhibited a value better than those of the conventional brazing fillermetals. Accordingly, the samples satisfying both the aforementionedConditions A and B satisfy Condition C.

[0214] Further, in both cases where the composition ratio of Au is 33wt. % as shown in Comparative Example 5-5 and where the compositionratio of Ag is 4 wt. % as shown in Comparative Example 5-7, any of thesamples is insufficient in wettability against stainless steel.Therefore, even when the aforementioned Conditions A and B aresatisfied, it is preferable that the composition ratio of Au is morethan 33 wt. %, and the composition ratio of Ag is more than 4 wt. %. Inparticular, in order to further improve wettability against stainlesssteel, it can be said, from Examples 5-10 and 5-11, that it ispreferable to satisfy the following two conditions.

[0215] The composition ratio of Au is in a range of about 51 to about 56wt. %.

[0216] The composition ratio of Ag is in a range of about 5 to about 20wt. %.

[0217] Besides, in consideration of the wettability against stainlesssteel, the composition ratio of Pd is preferably less than 34 wt. %. Byadding Pd, the color of the brazing filler metal increases in grade ofsilver gray to be closer to the color of stainless steel. As a result,when the stainless steel members are brazed, a portion thereof joinedcan be made less conspicuous.

[0218] As described in the foregoing, the Au—Ag—Cu—Pd based brazingfiller metal becomes a brazing filler metal satisfying all of the threerequirements, that is, enabling low temperature joining and securingexcellent corrosion resistance and sufficient joining strength, providedthat the composition ratios of the first additive element, Au, and Pdfall within the aforementioned ranges satisfying Condition A, and thecomposition ratio of Ag falls within the range satisfying Condition B.Furthermore, provided that the composition ratio of Au, Ag, or Pd iswithin the above-described range for excellent wettability againststainless steel, the Au—Ag—Cu—Pd based brazing filler metal is improvedin wettability against stainless steel. In this case, the brazing fillermetal spreads extensively on the surfaces of the stainless steelmembers, thus facilitating the joining work, and, as a result, thebrazing filler metal becomes more preferable.

[0219] Since the Au—Ag—Cu—Pd based brazing filler metal composed ofthose metal elements at respective specified ratios as described aboveis produced by adding Pd and the first additive element to Au—Ag—Cu,there is a conceivable composition utilizing a eutectic of Ag—Cu and aeutectic of the above-described additive element. Furthermore, Ag mightform a eutectic composition with the additive element (for example, Si),and Pd might form a eutectic composition with the additive element (forexample, Ge). It can be reasoned that this brazing filler metal islowered in temperature due to the formation of these eutectics.Therefore, the respective composition ratios of Au, Ag, Cu, Pd, and theadditive element, composing the Au—Ag—Cu—Pd based brazing filler metal,have respective ranges required for obtaining the brazing filler metalas the object of the invention, and it is reasoned that the respectivecomposition ratios fall within the ranges found from the results of thetests shown in Tables 10 and 11 described above.

[0220] To sum up, it is reasoned that the Au—Ag—Cu—Pd based brazingfiller metal according to the invention is turned into a brazing fillermetal which is capable of low temperature joining and is excellent bothin joining strength and corrosion resistance, utilizing at least the twoeutectics, that is, the eutectic of Ag—Cu and the eutectic of theadditive element, provided that the same satisfies all of the followingconditions 24) to 27).

[0221] Condition 24) The total composition ratio of the first additiveelement is in a range of more than 1 wt. % to less than 38 wt. %.

[0222] Condition 25) The composition ratio of Au is less than 82 wt. %.

[0223] Condition 26) The composition ratio of Pd is less than 34 wt. %.

[0224] Condition 27) The composition ratio of Ag is less than 47 wt. %.

[0225] Further, the Au—Ag—Cu—Pd based brazing filler metal even with theabove composition can be improved in wettability against stainlesssteel, provided that the same satisfies both the following conditions28) and 29).

[0226] Condition 28) The composition ratio of Au is more than 33 wt. %.

[0227] Condition 29) The composition ratio of Ag is more than 4 wt. %.

[0228] Furthermore, the Au—Ag—Cu—Pd based brazing filler metal can befurther improved in wettability against stainless steel, provided thatthe same satisfies both the following conditions 30) and 31).

[0229] Condition 30) The composition ratio of Au is in a range of about51 to about 56 wt. %.

[0230] Condition 31) The composition ratio of Ag is in a range of about5 to about 20 wt. %.

[0231] (Sixth Brazing Filler Metal)

[0232] Subsequently, a Au—Ag—Cu—Pd based brazing filler metal which is asixth brazing filler metal according to the invention is describedhereinafter. This brazing filler metal is different from the fifthbrazing filler metal in that a second additive element is added thereto,in addition to the first additive element. The second additive elementhere is at least one of metal elements, manganese (Mn) and lithium (Li).This brazing filler metal is also different in element but is producedby the same method as that of the first brazing filler metal.

[0233] Thirteen samples being Examples numbered from 6-1 to 6-13 shownin Table 12 and 11 samples being Comparative Examples numbered from 6-1to 611 shown in Table 13, 24 samples, in total, of different Au—Ag—Cu—Pdbased brazing filler metals, were prepared by varying a compositionratio (wt. %) of each of Au, Ag, Cu, and Pd as appropriate as well asvarying the kind and a composition ratio (wt. %) of each of the elementsconstituting the first additive element as appropriate, and varying acomposition ratio (wt. %) of each of the elements constituting thesecond additive element as appropriate. In this event, the samples wereprepared using one kind of element out of Si, Pb, and Sb and using twoor more kinds of elements out of them as the first additive element. Thetwo or more kinds of elements of the additive element are as follows:

[0234] Te and Si (Example 6-2); Ge, Sn, and Ga (Example 6-3)

[0235] Al, Sn, and Bi (Example 6-4); Ge, Sn, and Sb (Example 6-5)

[0236] Sb, Sn, and Pb (Example 6-6)

[0237] Sn and Al (Example 6-7, Comparative Example 6-5)

[0238] Bi and Ge (Example 6-8); Si and In (Example 6-9, ComparativeExample 6-6)

[0239] Ge and Pb (Example 6-10, Comparative Example 6-7)

[0240] In and Ga (Example 6-11)

[0241] In and Sn (Example 6-12, Comparative Example 6-8)

[0242] In and Ti (Example 6-13, Comparative Example 6-9)

[0243] In, Ge, and Ga (Comparative Example 6-3); Ga, Si and Al(Comparative Example 6-4)

[0244] Sn and Sb (Comparative Example 6-10); Sn and Te (ComparativeExample 6-11)

[0245] The respective prepared samples were examined in properties onthe selected six items which are the same as those of the first brazingfiller metal. It should be noted that the indication of “Example” and“Comparative Example” is the same as that of the first brazing fillermetal. The e) joining strength and f) corrosion resistance are checkedin the same manner as that of the first brazing filler metal.

[0246] As shown in Tables 12 and 13, the melting points of the samplesof Examples 6-1 to 6-13 are 644° C. (Examples 6-1, 6-9, and 6-13) evenat the maximum, and the melting point of any of the samples is thus nothigher than 800° C. The melting points of the samples of ComparativeExamples 6-1 to 6-4, 6-6, and 6-9 to 6-11, however, exceed 800° C.Regarding the wettability against SUS316L, while the samples of Examples6-1 to 6-13 provided excellent results, any of the samples ofComparative Examples 6-1 to 6-7 other than Comparative Examples 6-8 to6-11 provided a just slightly good result which was not sufficient.Besides, the brazing temperature for any of the samples of Examples 6-1to 6-13 was lower than 800° C. Crystal coarsening of SUS316L occurred inthe samples of Comparative Examples 6-1 to 6-4, 6-6, and 6-9 to 6-11,and not in the other samples. The joining strengths of the samples were590 MPa even at the minimum, and any of them was better than those ofthe conventional brazing filler metals. Regarding the corrosionresistance, any of samples other than Comparative Example 6-8 exhibitedan excellent result.

[0247] The Au—Ag—Cu—Pd based brazing filler metal also needs to satisfythe above-described three conditions A, B and C, and, from the resultsshown in Tables 12 and 13, the conditions for satisfaction are asfollows:

[0248] Condition A)

[0249] Since Comparative Examples 6-1 to 6-4, 6-6, and 6-9 to 6-11 andExamples 6-1 to 6-13 have common ranges of respective composition ratiosof Au, Ag, and Cu, it is difficult to specify Condition A based only onthe respective composition ratios of Au, Ag, and Cu.

[0250] Next, when the total composition ratio of the first additiveelement is no more than 1 wt. % and when it reaches 38 wt. % as shown inComparative Examples 6-1 to 6-4, the melting points exceed 800° C., sothat samples thereof do not satisfy Condition A. However, any of samplessatisfying Condition A as shown in Example 6-1 to 6-13 has a totalcomposition ratio of the first additive element which is in a range ofmore than 1 wt. % to less than 38 wt. %. Therefore, to satisfy ConditionA, the total composition ratio of the first additive element needs to bein a range of more than 1 wt. % to less than 38 wt. %. In this point ofview, it can be said, particularly on the basis of values shown inExamples 6-1 to 6-13, that the total composition ratio of the firstadditive element is preferably in a range of about 2 to about 37 wt. %.However, even if the total composition ratio of the first additiveelement is within this range, when the composition ratio of Au reaches78 wt. % as shown in Comparative Example 6-6, the melting point exceeds800° C., so that the sample does not satisfy Condition A. In contrast tothis, when the composition ratio of Au is less than 78 wt. % as shown inExamples 6-1 to 6-13, any of the samples satisfies Condition A.Accordingly, in order to satisfy Condition A, the composition ratio ofAu is only required to be less than 78 wt. %. Further, even if thecomposition ratio of Au is within this range, when the second additiveelement is added at the composition ratio 3 wt. % in total as shown inComparative Examples 6-10 and 6-11, the melting points exceed 800° C.,so that the samples do not satisfy Condition A. Accordingly, in order tosatisfy Condition A, the total composition ratio of the second additiveelement needs to be less than 3 wt. %. Further, when the compositionratio of Pd reaches 32 wt. % as shown in Comparative Example 6-9, themelting point exceeds 800° C., so that the sample does not satisfyCondition A. However, if the composition ratio of Pd is less than 32 wt.%, any of the samples satisfies Condition A. Accordingly, in order tosatisfy Condition A, the composition ratio of Pd is only required to beless than 32 wt. %, and is preferably not more than about 31 wt. %.

[0251] Condition B)

[0252] Only the sample of Comparative Example 6-8 is insufficient andthe other samples are excellent in corrosion resistance. The sampleshown in Comparative Example 6-8 has a composition ratio of Ag at 48 wt.%, and any of the other samples has a composition ratio of Ag at lessthan 48 wt. %. Accordingly, Condition B is satisfied when thecomposition ratio of Ag is less than 48 wt. %.

[0253] Condition C)

[0254] The samples satisfying both the aforementioned Conditions A and Bhave joining strengths of 590 MPa even at the minimum, and any of themexhibited a value better than those of the conventional brazing fillermetals. Accordingly, the samples satisfying both the aforementionedConditions A and B satisfy Condition C.

[0255] Further, in both cases where the composition ratio of Au is 33wt. % as shown in Comparative Example 6-5 and where the compositionratio of Ag is 5 wt. % as shown in Comparative Example 6-7, any of thesamples is insufficient in wettability against stainless steel.Therefore, even when the aforementioned Conditions A and B aresatisfied, it is preferable that the composition ratio of Au is morethan 33 wt. %, and the composition ratio of Ag is more than 5 wt. %. Inparticular, from any of the samples of Examples 6-1 to 6-13 beingexcellent in wettability, it is preferable to satisfy the following twomore conditions. It can be said that this results from the effect oflowering the melting point by the second additive element.

[0256] The composition ratio of Au is in a range of about 34 to about 77wt. %.

[0257] The composition ratio of Ag is in a range of about 6 to about 47wt. %.

[0258] As described in the foregoing, the Au—Ag—Cu—Pd based brazingfiller metal becomes a brazing filler metal satisfying all of the threerequirements, that is, enabling low temperature joining and securingexcellent corrosion resistance and sufficient joining strength, providedthat the composition ratios of the first and second additive elements,Au, and Pd fall within the ranges satisfying Condition A, and thecomposition ratio of Ag falls within the range satisfying Condition B.Furthermore, provided that the composition ratios of Au and Ag aterespectively within the above-described ranges for excellent wettabilityagainst stainless steel, the Au—Ag—Cu—Pd based brazing filler metal isimproved in wettability against stainless steel. In this case, thebrazing filler metal spreads extensively on the surfaces of thestainless steel members, thus facilitating the joining work, and, as aresult, the brazing filler metal becomes more preferable.

[0259] Since the Au—Ag—Cu—Pd based brazing filler metal composed ofthose metal elements at respective specified ratios as described aboveis produced by adding Pd and the first and second additive elements toAu—Ag—Cu, there is a conceivable composition utilizing a eutectic ofAg—Cu and the above-described eutectic of additive element. Furthermore,Ag might form a eutectic composition with the first additive element(for example, Si), and Pd might form a eutectic composition with thefirst additive element (for example, Ge). It can be reasoned that thisbrazing filler metal is lowered in temperature due to the formation ofthese eutectic compositions. Moreover, since Mn or Li being the secondadditive element has the effect of lowering the melting point, it can bereasoned that the melting point of the Au—Ag—Cu—Pd based brazing fillermetal is lowered due to the addition of the second additive element.Therefore, the respective composition ratios of Au, Ag, Cu, Pd, and thefirst and second additive elements, composing the Au—Ag—Cu—Pd basedbrazing filler metal, have respective ranges required for obtaining thebrazing filler metal as the object of the invention, and it is reasonedthat the respective composition ratios fall within the ranges found fromthe results of the tests shown in Tables 12 and 13 described above.

[0260] To sum up, the Au—Ag—Cu—Pd based brazing filler metal accordingto the invention is turned into a brazing filler metal which is capableof low temperature joining and is excellent both in joining strength andcorrosion resistance, utilizing at least the two eutectics, that is, theeutectic of Ag—Cu and the eutectic of additive element, provided thatthe same satisfies all of the following conditions 32) to 36).

[0261] Condition 32) The total composition ratio of at least one kind ofelement of the first additive element is in a range of more than 1 toless than 38 wt. %.

[0262] Condition 33) The composition ratio of Au is less than 78 wt. %.

[0263] Condition 34) The total composition ratio of the second additiveelement is less than 3 wt. %.

[0264] Condition 35) The composition ratio of Pd is less than 32 wt. %.

[0265] Condition 36) The composition ratio of Ag is less than 48 wt. %.

[0266] Further, the Au—Ag—Cu—Pd based brazing filler metal even with theabove composition can be improved in wettability against stainlesssteel, provided that the same satisfies both the following conditions37) and 38).

[0267] Condition 37) The composition ratio of Au is more than 33 wt. %.

[0268] Condition 38) The composition ratio of Ag is more than 5 wt. %.

[0269] Furthermore, the Au—Ag—Cu—Pd based brazing filler metal can befurther improved in wettability against stainless steel, provided thatthe same satisfies both the following conditions 39) and 40).

[0270] Condition 39) The composition ratio of Au is in a range of about34 to about 77 wt. %.

[0271] Condition 40) The composition ratio of Ag is in a range of about6 to about 47 wt. %.

[0272] (Seventh Brazing Filler Metal)

[0273] Subsequently, a Au—Ag—Cu—Pd—Ni based brazing filler metal whichis a seventh brazing filler metal according to the invention isdescribed hereinafter. This brazing filler metal is composed of, as mainconstituents, five kinds of elements Au, Ag, Cu, Pd having homogeneoussolubility with Au, Ag, and Cu added thereto, and Ni having homogeneoussolubility with Au and Cu added thereto, with a first additive elementand a second additive element added to the main constituents. The firstand second additive elements are the same as those of the sixth brazingfiller metal. This Au—Ag—Cu—Pd—Ni based brazing filler metal isdifferent in element but is produced by the same method as that of thefirst brazing filler metal.

[0274] Fourteen samples being Examples numbered from 7-1 to 7-14 shownin Table 14 and 12 samples being Comparative Examples numbered from 7-1to 712 shown in Table 15, 26 samples, in total, of differentAu—Ag—Cu—Pd—Ni based brazing filler metals, were prepared by varying acomposition ratio (wt. %) of each of Au, Ag, Cu, Pd, and Ni asappropriate as well as varying the kind and a composition ratio (wt. %)of each of the elements constituting the first additive element asappropriate, and varying a composition ratio (wt. %) of each of theelements constituting the second additive element as appropriate. Inthis event, the samples were prepared using one kind of element out ofSi, Tl, and Pb and using two or more kinds of elements out of them asthe first additive element. The two or more kinds of elements of thefirst additive element are as follows:

[0275] Ge and In (Example 7-2); Pb, Sn, and In (Example 7-3)

[0276] Sn, Sb and Bi (Example 7-4); Ge, Al, and Tl (Example 7-5)

[0277] Bi, In, and Si (Example 7-6)

[0278] Ge and Bi (Example 7-7, Comparative Example 7-5)

[0279] In and Si (Examples 7-8 and 7-12, Comparative Example 7-8)

[0280] Al and Te (Example 7-9, Comparative Example 7-6)

[0281] Sn and Tl (Example 7-10, Comparative Example 7-7)

[0282] Ga and Al (Example 7-11)

[0283] Bi and Sb (Example 7-13, Comparative Example 7-9)

[0284] Ge and Te (Example 7-14, Comparative Example 7-12)

[0285] Si, In, and Al (Comparative Example 7-3); Bi, Ga, and Ge(Comparative Example 7-4)

[0286] Sn and Sb (Comparative Example 7-10); Ge and Al (ComparativeExample 7-11)

[0287] The respective prepared samples were examined in properties onthe selected six items which are the same as those of the first brazingfiller metal. It should be noted that the indication of “Example” and“Comparative Example” is the same as that of the first brazing fillermetal. The e) joining strength and f) corrosion resistance are checkedin the same manner as that of the first brazing filler metal.

[0288] As shown in Tables 14 and 15, the melting points of the samplesof Examples 7-1 to 7-14 are 732° C. (Example 7-14) even at the maximum,and the melting point of any of the samples is thus not higher than 800°C. The melting points of the brazing filler metals of ComparativeExamples 7-1 to 7-4, 7-6, and 7-9 to 7-12, however, exceed 800° C.Regarding the wettability against SUS316L, while the samples of Examples7-1 to 7-14 provided excellent results, any of the samples ofComparative Examples other than Comparative Examples 7-8 to 7-11provided a just slightly good result which was not sufficient. Besides,the brazing temperature for any of the samples of Examples 7-1 to 7-14was lower than 800° C. Crystal coarsening of SUS316L occurred inComparative Examples 7-1 to 7-4, 7-6, and 7-9 to 7-12, and not in theother samples. The joining strengths of the samples were 640 MPa even atthe minimum, and any of them was better than those of the conventionalbrazing filler metals. Regarding the corrosion resistance, any of thesamples other than Comparative Example 7-8 exhibited an excellentresult.

[0289] From the results shown in Tables 14 and 15, the conditions forthe Au—Ag—Cu—Pd—Ni based brazing filler metal to satisfy theabove-described three conditions A, B and C, are as follows:

[0290] Condition A)

[0291] Since Comparative Examples 7-1 to 7-4, 7-6, and 7-9 to 7-12 andExamples 7-1 to 7-13 have common ranges of respective composition ratiosof Au, Ag, and Cu, it is difficult to specify Condition A based only onthe respective composition ratios of Au, Ag, and Cu.

[0292] Next, when the total composition ratio of the first additiveelement is no more than 1 wt. % and when it is 35 wt. % as shown inComparative Examples 7-1 to 7-4, the melting points exceed 800° C., sothat samples thereof do not satisfy Condition A. However, any of samplessatisfying Condition A as shown in Example 7-1 to 7-14 has a totalcomposition ratio of the first additive element which is in a range ofmore than 1 wt. % to less than 35 wt. %. Therefore, to satisfy ConditionA, the total composition ratio of the first additive element needs to bein a range of more than 1 wt. % to less than 35 wt. %. In this point ofview, it can be said, particularly on the basis of values shown inExamples 7-1 to 7-14, that the total composition ratio of the firstadditive element is preferably in a range of about 2 to about 34 wt. %.However, even if the total composition ratio of the first additiveelement is within this range, when the composition ratio of Au reaches74 wt. % as shown in Comparative Example 7-6, the melting point exceeds800° C., so that the sample does not satisfy Condition A. In contrast tothis, when the composition ratio of Au is less than 74 wt. % as shown inExamples 7-1 to 7-14, any of the samples satisfies Condition A.Accordingly, in order to satisfy Condition A, the composition ratio ofAu is only required to be less than 74 wt. %. Further, even if thecomposition ratio of Au is within this range, when the second additiveelement is added at the composition ratio 3 wt. % in total as shown inComparative Examples 7-10 and 7-11, the melting points exceed 800° C.,so that the samples do not satisfy Condition A. Accordingly, in order tosatisfy Condition A, the total composition ratio of the second additiveelement needs to be less than 3 wt. %. Further, when the compositionratio of Pd reaches 31 wt. % as shown in Comparative Example 7-9, themelting point exceeds 800° C., so that the sample does not satisfyCondition A. However, if the composition ratio of Pd is less than 31 wt.%, any of the samples satisfies Condition A. Accordingly, in order tosatisfy Condition A, the composition ratio of Pd needs to be less than31 wt. %. Further, when the composition ratio of Ni reaches 16 wt. % asshown in Comparative Example 712, the melting point exceeds 800° C., sothat the sample does not satisfy Condition A. However, if thecomposition ratio of Ni is less than 16 wt. %, any of the samplessatisfies Condition A. Accordingly, in order to satisfy Condition A, thecomposition ratio of Ni is only required to be less than 16 wt. %, andis preferably not more than about 15 wt. %.

[0293] Condition B)

[0294] Only the sample of Comparative Example 7-8 is insufficient andthe other samples are excellent in corrosion resistance. The sampleshown in Comparative Example 7-8 has a composition ratio of Ag at 47 wt.%, and any of the other samples has a composition ratio of Ag at lessthan 47 wt. %. Accordingly, Condition B is satisfied when thecomposition ratio of Ag is less than 47 wt. %.

[0295] Condition C)

[0296] The samples satisfying both the aforementioned Conditions A and Bhave joining strengths of 640 MPa even at the minimum, and any of themexhibited a value better than those of the conventional brazing fillermetals. Accordingly, the samples satisfying both the aforementionedConditions A and B satisfy Condition C. The Au—Ag—Cu—Pd—Ni based brazingfiller metal is better than each of the first, fifth and sixth brazingfiller metals in joining strength. It can be said that this results fromthe addition of Ni.

[0297] On the other hand, in both cases where the composition ratio ofAu is 35 wt. % as shown in Comparative Example 7-5 and where thecomposition ratio of Ag is 6 wt. % as shown in Comparative Example 7-7,any of the samples is insufficient in wettability against stainlesssteel. Therefore, even when the aforementioned Conditions A and B aresatisfied, it is preferable that the composition ratio of Au is morethan 35 wt. %, and the composition ratio of Ag is more than 6 wt. %.

[0298] From Examples 7-1 to 7-14, in order to improve the wettabilityagainst stainless steel, it is preferable to satisfy the following twoconditions. It can be said that the improvement in wettability resultsfrom the effect of lowering the melting point by the second additiveelement.

[0299] The composition ratio of Au is in a range of about 36 to about 73wt. %.

[0300] The composition ratio of Ag is in a range of about 7 to about 46wt. %.

[0301] As described in the foregoing, the Au—Ag—Cu—Pd—Ni based brazingfiller metal becomes a brazing filler metal satisfying all of the threerequirements, that is, enabling low temperature joining and securingexcellent corrosion resistance and sufficient joining strength, providedthat the composition ratios of the first and second additive elements,Au, Pd, and Ni fall within the ranges satisfying Condition A, and thecomposition ratio of Ag falls within the range satisfying Condition B.Furthermore, provided that the composition ratios of Au and Ag arerespectively within the above-described ranges for excellent wettabilityagainst stainless steel, the Au—Ag—Cu—Pd—Ni based brazing filler metalis improved in wettability against stainless steel. In this case, thebrazing filler metal spreads extensively on the surfaces of thestainless steel members, thus facilitating the joining work, and, as aresult, the brazing filler metal becomes more preferable.

[0302] Since there is a conceivable composition of the Au—Ag—Cu—Pd—Nibased brazing filler metal utilizing a eutectic of Ag—Cu and theabove-described eutectic of additive element, it can be reasoned thatthis brazing filler metal is lowered in temperature due to the formationof these eutectics. Furthermore, Ag or Pd might form a eutecticcomposition with the first additive element (for example, Ge). Further,since Mn or Li being the second additive element has the effect oflowering the melting point, it is reasoned that the melting point of theAu—Ag—Cu—Pd—Ni based brazing filler metal is lowered due to the additionof the second additive element. Therefore, the respective compositionratios of Au, Ag, Cu, Pd, and Ni, and the first and second additiveelements, composing the Au—Ag—Cu—Pd—Ni based brazing filler metal haveranges required for obtaining the brazing filler metal as the object ofthe invention, and it is reasoned that the composition ratios fallwithin the ranges found from the results of the tests shown in Tables 14and 15 described above.

[0303] To sum up, it is reasoned that the Au—Ag—Cu—Pd—Ni based brazingfiller metal according to the invention is turned into a brazing fillermetal which is capable of low temperature joining and is excellent bothin joining strength and corrosion resistance, utilizing the eutectic ofAg—Cu and the eutectics of additive elements, provided that the samesatisfies all of the following conditions 41) to 46).

[0304] Condition 41) The total composition ratio of at least one kind ofelement of the first additive element is in a range of more than 1 wt. %to less than 35 wt. %.

[0305] Condition 42) The composition ratio of Au is less than 74 wt. %.

[0306] Condition 43) The total composition ratio of the second additiveelement is less than 3 wt. %.

[0307] Condition 44) The composition ratio of Pd is less than 31 wt. %.

[0308] Condition 45) The composition ratio of Ni is less than 16 wt. %.

[0309] Condition 46) The composition ratio of Ag is less than 47 wt. %.

[0310] Further, the Au—Ag—Cu—Pd—Ni based brazing filler metal even withthe above composition can be improved in wettability against stainlesssteel, provided that the same satisfies both the following conditions47) and 48).

[0311] Condition 47) The composition ratio of Au is more than 35 wt. %.

[0312] Condition 48) The composition ratio of Ag is more than 6 wt. %.

[0313] Furthermore, the Au—Ag—Cu—Pd—Ni based brazing filler metal can befurther improved in wettability against stainless steel, provided thatthe same satisfies both the following conditions 49) and 50).

[0314] Condition 49) The composition ratio of Au is in a range of about36 to about 73 wt. %.

[0315] Condition 50) The composition ratio of Ag is in a range of about7 to about 46 wt. %.

[0316] (Eighth Brazing Filler Metal)

[0317] Subsequently, a Au—Ag—Cu—Pd—Ge based brazing filler metal whichis an eighth brazing filler metal according to the invention isdescribed hereinafter. This brazing filler metal is composed of elementsAu, Ag, Cu, Pd having homogeneous solubility with Au, Ag, and Cu addedthereto, and Ge added thereto, and is thus produced by limiting thefirst additive element of the above-described fifth brazing filler metalonly to one kind of element Ge. This eighth brazing filler metal is alsodifferent in element but is produced by the same method as that of thefirst brazing filler metal.

[0318] Nine samples being Examples numbered from 8-1 to 8-9 shown inTable 16 and 7 samples being Comparative Examples numbered from 8-1 to8-7, 16 samples, in total, of different Au—Ag—Cu—Pd—Ge based brazingfiller metals, were prepared by varying a composition ratio (wt. %) ofeach of Au, Ag, Cu, Pd, and Ge as appropriate. The respective preparedsamples were examined, similarly to the second brazing filler metal, onthe two items, a) melting point and c) wettability against SUS316L. Thesamples of Examples 8-7 to 8-9 and Comparative Examples 8-5 and 8-6 wereexamined on the other four items b),

[0319] d), e), and f). The results thereof are as shown in Table 17. Itshould be noted that the indication of “Example” and “ComparativeExample” is the same as that of the first brazing filler metal. The e)joining strength and f) corrosion resistance are checked in the samemanner as that of the first brazing filler metal.

[0320] As shown in Table 16, the melting points of the brazing fillermetals of Examples 8-1 to 8-9 are 740° C. (Example 8-3) even at themaximum, and the melting point of any of the samples is thus not higherthan 800° C. The melting points of the brazing filler metals ofComparative Examples 8-1 to 8-4 and 8-7, however, exceed 800° C.Regarding the wettability against SUS316L, while the samples of Examples8-1 to 8-9 provided excellent results, the samples of ComparativeExamples 8-1 to 8-5 provided just slightly good results which were notsufficient. Besides, as shown in Table 17, while the brazing temperaturefor the sample of Comparative Example 8-5 exceeded 800° C., that for anyof the other samples was lower than 800° C. Crystal coarsening ofSUS316L occurred in the sample of Comparative Example 8-5, and not inthe other samples. The joining strengths of the samples were 730 MPaeven at the minimum, and any of them was better than those of theconventional brazing filler metals. Regarding the corrosion resistance,any of the samples other than Comparative Example 8-6 exhibited anexcellent result.

[0321] From the results shown in Tables 16 and 17, the conditions forthe Au—Ag—Cu—Pd—Ge based brazing filler metal to satisfy theabove-described three conditions A, B and C, are as follows:

[0322] Condition A)

[0323] Since Comparative Examples 8-1 to 8-4 and 8-7 and Examples 8-1 to8-9 have common ranges of respective composition ratios of Au, Ag, andCu, it is difficult to specify Condition A based only on the respectivecomposition ratios of Au, Ag, and Cu.

[0324] Next, when the composition ratio of Ge is 4 wt. % and 26 wt. % asshown in Comparative Examples 8-1 and 8-2, the melting points exceed800° C., so that samples thereof do not satisfy Condition A. However, ifthe composition ratio of Ge is in a range of more than 4 wt. % to lessthan 26 wt. % as shown in Example 8-1 to 8-9, the samples satisfyCondition A. Therefore, to satisfy Condition A, the composition ratio ofGe needs to be in a range of more than 4 wt. % to less than 26 wt. %. Inthis point of view, it can be said, particularly on the basis of valuesshown in Examples 8-1 to 8-9, that the composition ratio of Ge ispreferably in a range of about 5 to about 25 wt. %. However, even if thecomposition ratio of Ge is within this range, when the composition ratioof Au reaches 28 wt. % as shown in Comparative Example 8-3 and when thecomposition ratio of Au reaches 76 wt. % as shown in Comparative Example8-4, the melting points exceed 800° C., so that the samples do notsatisfy Condition A. In contrast to this, when the composition ratio ofAu is in a range of more than 28 wt. % to less than 76 wt. % as shown inExamples 8-1 to 8-9, the melting points become lower than 800° C., sothat the samples satisfy Condition A. Accordingly, in order to satisfyCondition A, the composition ratio of Au needs to be in a range of morethan 28 wt. % to less than 76 wt. %. Further, even if the compositionratio of Au is limited to this range, when the composition ratio of Pdreaches 36 wt. % as shown in Comparative Example 8-7, the sample doesnot satisfy Condition A. However, if the composition ratio of Pd is lessthan 36 wt. % as in Examples 8-1 to 8-9, the samples satisfy ConditionA. Accordingly, in order to satisfy Condition A, the composition ratioof Pd is only required to be less than 36 wt. %, and is preferably notmore than about 35 wt. %.

[0325] Condition B)

[0326] Only the sample of Comparative Example 8-6 is insufficient andthe other samples are excellent in corrosion resistance. The sampleshown in Comparative Example 8-6 has a composition ratio of Ag at 51 wt.%, and any of the other samples has a composition ratio of Ag at lessthan 51 wt. %. Accordingly, Condition B is satisfied when thecomposition ratio of Ag is less than 51 wt. %.

[0327] Condition C)

[0328] The samples satisfying both the aforementioned Conditions A and Bhave joining strengths of 730 MPa even at the minimum, and any of themexhibited a value better than those of the conventional brazing fillermetals. Accordingly, the samples satisfying both the aforementionedConditions A and B satisfy Condition C.

[0329] Further, even the samples satisfying Conditions A and B can beparticularly improved in wettability against stainless steel, providedthat Au and Ag satisfy both the following conditions as in Examples 8-4to 8-9.

[0330] The composition ratio of Au is in a range of about 29 to about 75wt. %.

[0331] The composition ratio of Ag is in a range of about 5 to about 50wt. %.

[0332] As described in the foregoing, the Au—Ag—Cu—Pd—Ge based brazingfiller metal becomes a brazing filler metal satisfying all of the threerequirements, that is, enabling low temperature joining and securingexcellent corrosion resistance and sufficient joining strength, providedthat the composition ratios of Ge, Au, and Pd fall within the rangessatisfying Condition A, and the composition ratio of Ag falls within therange satisfying Condition B. Furthermore, provided that the compositionratios of Au and Ag are respectively within the above-described rangesfor excellent wettability against stainless steel, the Au—Ag—Cu—Pd—Gebased brazing filler metal is improved in wettability against stainlesssteel. In particular, by adding Pd at a composition ratio of less than35 wt. %, the color of the brazing filler metal preferably becomessilver gray.

[0333] Besides, the Au—Ag—Cu—Pd—Ge based brazing filler metal containsPd and Ge. The melting point of a Pd—Ge alloy is gradually lowered fromabout 938° C. according as the composition ratio of Pd is increased asshown in FIG. 16. Upon the composition ratio of Pd reaching about 45 wt.%, the melting point reaches the lowest temperature of about 725° C. andthereafter repeatedly rises and falls twice, and upon the compositionratio of Pd reaching 100, the melting point reaches about 1555° C. Thereoccurs a eutectic composition of the Pd—Ge alloy in this state where themelting point is at the lowest. A state of such a eutectic compositionis designated as a eutectic of Pd—Ge. In this point of view, it isreasoned that the melting point of the Au—Ag—Cu—Pd—Ge based brazingfiller metal is lowest when the same has a composition capable ofutilizing the eutectic of Pd—Ge in addition to a eutectic of Ag—Cu, aeutectic of Au—Ge, a eutectic of Ag—Ge, and a eutectic of Cu—Ge,similarly to the second brazing filler metal. Therefore, the respectivecomposition ratios of Au, Ag, Cu, Pd, and Ge, composing theAu—Ag—Cu—Pd—Ge based brazing filler metal, have respective rangesrequired for obtaining the brazing filler metal as the object of theinvention, and it is reasoned that the respective composition ratiosfall within the ranges found from the results of the tests shown inTables 16 and 17 described above.

[0334] To sum up, it is reasoned that the Au—Ag—Cu—Pd—Ge based brazingfiller metal according to the invention is turned into a brazing fillermetal which is capable of low temperature joining and is excellent bothin joining strength and corrosion resistance, utilizing five eutectics,that is, the eutectic of Ag—Cu, the eutectic of Au—Ge, the eutectic ofAg—Ge, the eutectic of Cu—Ge, and the eutectic of Pd—Ge, provided thatthe same satisfies all of the following conditions 51) to 54).

[0335] Condition 51) The composition ratio of Ge is in a range of morethan 4 wt. % to less than 26 wt. %.

[0336] Condition 52) The composition ratio of Au is in a range of morethan 28 wt. % to less than 76 wt. %.

[0337] Condition 53) The composition ratio of Pd is less than 36 wt. %.

[0338] Condition 54) The composition ratio of Ag is less than 51 wt. %.

[0339] Furthermore, the Au—Ag—Cu—Pd—Ge based brazing filler metal withthe composition satisfying the above conditions can be improved inwettability against stainless steel, provided that the compositionratios of Au and Ag satisfy both the following conditions 55) and 56).

[0340] Condition 55) The composition ratio of Au is in a range of about29 to about 75 wt. %.

[0341] Condition 56) The composition ratio of Ag is in a range of about5 to about 50 wt. %.

[0342] (Ninth Brazing Filler Metal)

[0343] Subsequently, a Au—Ag—Cu—Pd—Si based brazing filler metal whichis a ninth brazing filler metal according to the invention is describedhereinafter. This brazing filler metal is composed of elements Au, Ag,Cu, Pd having homogeneous solubility with Au, Ag, and Cu added thereto,and Si added thereto, and is thus produced by limiting the firstadditive element of the above-described fifth brazing filler metal onlyto one kind of element Si. This ninth based brazing filler metal is alsodifferent in element but is produced by the same method as that of thefirst brazing filler metal.

[0344] Nine samples being Examples numbered from 9-1 to 9-9 shown inTable 18 and 7 samples being Comparative Examples numbered from 9-1 to9-7, 16 samples, in total, of different Au—Ag—Cu—Pd—Si based brazingfiller metals, were prepared by varying a composition ratio (wt. %) ofeach of Au, Ag, Cu, Pd, and Si as appropriate. The respective preparedsamples were examined, similarly to the second brazing filler metal, onthe two items, a) melting point and c) wettability against SUS316L. Thesamples of Examples 9-7 to 9-9 and two samples of Comparative Examples9-5 and 9-6 were examined on the other four items b), d), e), and f).The results thereof are as shown in Table 19. It should be noted thatthe indication of “Example” and “Comparative Example” is the same asthat of the first brazing filler metal. The e) joining strength and f)corrosion resistance are checked in the same manner as that of the firstbrazing filler metal.

[0345] As shown in Table 18, the melting points of the samples ofExamples 9-1 to 9-9 are 746° C. (Example 9-1) even at the maximum, andthe melting point of any of the samples is thus not higher than 800° C.The melting points of the samples of Comparative Examples 9-1 to 9-5 and9-7, however, exceed 800° C. Regarding the wettability against SUS316L,while the samples of Examples 9-1 to 9-9 provided excellent results, thesamples of Comparative Examples 9-1 to 95 provided just slightly goodresults which were not sufficient. Besides, as shown in Table 19, whilethe brazing temperature for the sample of Comparative Example 9-5exceeded 800° C., that for any of the other samples was lower than 800°C. Crystal coarsening of SUS316L occurred in the sample of ComparativeExample 9-5, and not in the other samples. The joining strengths of thesamples were 760 MPa even at the minimum, and any of them was betterthan those of the conventional brazing filler metals. Regarding thecorrosion resistance, any of the samples other than Comparative Example9-6 exhibited an excellent result.

[0346] From the results shown in Tables 18 and 19, the conditions forthe Au—Ag—Cu—Pd—Si based brazing filler metal to satisfy theabove-described three conditions A, B and C, are as follows:

[0347] Condition A)

[0348] Since Comparative Examples 9-1 to 9-5 and 9-7 and Examples 9-1 to9-9 have common ranges of respective composition ratios of Au, Ag, andCu, it is difficult to specify Condition A based only on the respectivecomposition ratios of Au, Ag, and Cu.

[0349] Next, when the composition ratio of Si is 0.9 wt. % and 17 wt. %as shown in Comparative Examples 9-1 and 9-2, the melting points exceed800° C., so that samples thereof do not satisfy Condition A. However,any of samples satisfying Condition A as shown in Example 9-1 to 9-9 hasa composition ratio of Si which is in a range of more than 0.9 wt. % toless than 17 wt. %. Therefore, to satisfy Condition A, the compositionratio of Si needs to be in a range of more than 0.9 wt. % to less than17 wt. %. In this point of view, it can be said, particularly on thebasis of values shown in Examples 9-1 to 9-3, that the composition ratioof Si is preferably in a range of about 1 to about 16 wt. %. However,even if the composition ratio of Si is within this range, when thecomposition ratio of Au reaches 30 wt. % as shown in Comparative Example9-3 and when the composition ratio of Au reaches 72 wt. % as shown inComparative Example 9-4, the melting points exceed 800° C., so that thesamples do not satisfy Condition A. In contrast to this, when thecomposition ratio of Au is in a range of more than 30 wt. % to less than72 wt. % as shown in Examples 9-1 to 9-9, the melting points becomelower than 800° C., so that the samples satisfy Condition A.Accordingly, in order to satisfy Condition A, the composition ratio ofAu needs to be in a range of more than 30 wt. % to less than 72 wt. %.Further, even if the composition ratio of Au is limited to this range,when the composition ratio of Pd reaches 38 wt. % as shown inComparative Example 9-7, the sample does not satisfy Condition A.However, if the composition ratio of Pd is less than 38 wt. % as inExamples 9-1 to 9-9, the samples satisfy Condition A. Accordingly, inorder to satisfy Condition A, the composition ratio of Pd needs to beless than 38 wt. %. Further, when the composition ratio of Ag reaches 2wt. % as shown in Comparative Example 9-5, the sample does not satisfyCondition A. However, if the composition ratio of Ag is more than 2 wt.% as in Examples 9-1 to 9-9, the samples satisfy Condition A.Accordingly, in order to satisfy Condition A, the composition ratio ofAg is only required to be more than 2 wt. %, and is preferably not lessthan about 3 wt. %.

[0350] Condition B)

[0351] Only the sample of Comparative Example 9-6 is insufficient andthe other samples are excellent in corrosion resistance. The sampleshown in Comparative Example 9-6 has a composition ratio of Ag at 34 wt.%, and any of the other samples has a composition ratio of Ag at lessthan 34 wt. %. Accordingly, Condition B is satisfied when thecomposition ratio of Ag is less than 34 wt. %.

[0352] Condition C)

[0353] The samples satisfying both the aforementioned Conditions A and Bhave joining strengths of 780 MPa even at the minimum, and any of themexhibited a value better than those of the conventional brazing fillermetals. Accordingly, the samples satisfying both the aforementionedConditions A and B satisfy Condition C.

[0354] Further, even the samples satisfying Conditions A and B can beparticularly improved in wettability against stainless steel, providedthat Au, Ag, and Pd satisfy all of the following conditions as inExamples 9-4 to 9-9.

[0355] The composition ratio of Au is in a range of about 40 to about 71wt. %.

[0356] The composition ratio of Ag is in a range of about 3 to about 32wt. %.

[0357] The composition ratio of Pd is in a range of about 5 to about 37wt. %.

[0358] As described in the foregoing, the Au—Ag—Cu—Pd—Si based brazingfiller metal becomes a brazing filler metal satisfying all of the threerequirements, that is, enabling low temperature joining and securingexcellent corrosion resistance and sufficient joining strength, providedthat the composition ratios of Si, Au, Pd, and Ag fall within the rangessatisfying Condition A, and the composition ratio of Ag falls within therange satisfying Condition B. In particular, by adding Pd at acomposition ratio of less than 38 wt. %, the color of the brazing fillermetal preferably becomes silver gray.

[0359] Besides, it is reasoned that since the ninth brazing filler metalis produced by adding Pd and Si to Au—Ag—Cu, the melting point of theninth brazing filler metal is lowered when the same has a compositionutilizing three eutectics, that is, a eutectic of Ag—Cu, a eutectic ofAu—Si, and a eutectic of Ag—Si, similarly to the third brazing fillermetal. Therefore, the respective composition ratios of Au, Ag, Cu, Pd,and Si, composing the Au—Ag—Cu—Pd—Si based brazing filler metal, haverespective ranges required for obtaining the brazing filler metal as theobject of the invention, and it is reasoned that the respectivecomposition ratios fall within the ranges found from the results of thetests shown in Tables 18 and 19 described above.

[0360] To sum up, it is reasoned that the Au—Ag—Cu—Pd—Si based brazingfiller metal according to the invention is turned into a brazing fillermetal which is capable of low temperature joining and is excellent bothin joining strength and corrosion resistance, utilizing the threeeutectics, that is, the eutectic of Ag—Cu, the eutectic of Au—Si, andthe eutectic of Ag—Si, provided that the same satisfies the followingconditions 57) to 60).

[0361] Condition 57) The composition ratio of Si is in a range of morethan 0.9 wt. % to less than 17 wt. %.

[0362] Condition 58) The composition ratio of Au is in a range of morethan 30 wt. % to less than 72 wt. %.

[0363] Condition 59) The composition ratio of Pd is less than 38 wt. %.

[0364] Condition 60) The composition ratio of Ag is in a range of morethan 2 wt. % to less than 34 wt. %.

[0365] Furthermore, the Au—Ag—Cu—Pd—Si based brazing filler metal withthe composition satisfying the above conditions can be improved inwettability against stainless steel, provided that the compositionratios of Au, Ag, and Pd satisfying all of the following conditions 61)and 63).

[0366] Condition 61) The composition ratio of Au is in a range of about40 to about 71 wt. %.

[0367] Condition 62) The composition ratio of Ag is in a range of about3 to about 32 wt. %.

[0368] Condition 63) The composition ratio of Pd is in a range of about5 to about 37 wt. %.

[0369] (Tenth Brazing Filler Metal)

[0370] Subsequently, a Au—Ag—Cu—Pd—Ge—Si—Sn based brazing filler metalwhich is a tenth brazing filler metal according to the invention isdescribed hereinafter. This brazing filler metal is composed of Au, Ag,Cu, Pd, and at least one kind of element out of Ge, Si, and Sn addedthereto, and is thus produced by limiting the first additive element ofthe above-described fifth brazing filler metal to the three kinds ofelements Ge, Si, and Sn. The tenth brazing filler metal is alsodifferent in element but is produced by the same method as that of thefirst brazing filler metal.

[0371] Twenty-seven samples being Examples numbered from 10-1 to 10-27shown in Table 20 and 12 samples being Comparative Examples numberedfrom 10-1 to 10-12 shown in Table 21, 39 samples, in total, of differentAu—Ag—Cu—Pd—Ge—Si—Sn based brazing filler metals, were prepared byvarying a composition ratio (wt. %) of each of Au, Ag, Cu, Pd, Ge, Si,and Sn as appropriate. The respective prepared samples were examined inproperties on the selected six items which are the same as those of thefirst brazing filler metal. It should be noted that the indication of“Example” and “Comparative Example” is the same as that of the firstbrazing filler metal. The e) joining strength and f) corrosionresistance are checked in the same manner as that of the first brazingfiller metal.

[0372] As shown in Tables 20 and 21, the melting points of the samplesof Examples 10-1 to 10-27 are 743° C. (Examples 10-3 and 10-27) even atthe maximum, and the melting point of any of the samples is thus nothigher than 800° C. The melting points of the samples of ComparativeExamples 10-1 to 107, 10-9, and 10-12, however, exceed 800° C. Regardingthe wettability against SUS316L, while the samples of Examples 10-1 to10-27 provided excellent results, the samples of Comparative Examples10-1 to 10-12 and 10-12 provided just slightly good results which werenot sufficient. Besides, the brazing temperature for any of the samplesof Examples 10-1 to 10-27 was lower than 800° C. Crystal coarsening ofSUS316L occurred in the samples of Comparative Examples 10-1 to 10-7,10-9, and 10-12, and not in the other samples. The joining strengths ofthe samples were 590 MPa even at the minimum, and any of them was betterthan those of the conventional brazing filler metals. Regarding thecorrosion resistance, any of the samples other than Comparative Example10-11 exhibited an excellent result.

[0373] From the results shown in Tables 20 and 21, the conditions forthe Au—Ag—Cu—Pd—Ge—Si—Sn based brazing filler metal to satisfy theabove-described three conditions A, B and C, are as follows:

[0374] Condition A)

[0375] Since Comparative Examples 10-1 to 10-7, 10-9, and 10-12 andExamples 10-1 to 10-27 have common ranges of respective compositionratios of Au, Ag, and Cu, it is difficult to specify Condition A basedonly on the respective composition ratios of Au, Ag, and Cu.

[0376] Next, when the total composition ratio of Ge, Si, and Sn is nomore than 1 wt. % and when it is 38 wt. % and 39 wt. % as shown inComparative Examples 10-1 to 10-7, the melting points exceed 800° C., sothat samples thereof do not satisfy Condition A. However, any of samplessatisfying Condition A as shown in Example 10-1 to 10-27 has a totalcomposition ratio of Ge, Si, and Sn which is in a range of more than 1wt. % to less than 38 wt. %. In this point of view, it can be said,particularly on the basis of values shown in Examples 10-1 to 10-27,that the total composition ratio of the Ge, Si, and Sn is preferably ina range of about 2 to about 37 wt. %. Further, even if the totalcomposition ratio of Ge, Si, and Sn is within this range, when thecomposition ratio of Au reaches 83 wt. % as shown in Comparative Example10-9, the melting point exceeds 800° C., so that the sample does notsatisfy Condition A. In contrast to this, when the composition ratio ofAu is less than 83 wt. % as shown in Examples 10-1 to 10-27, any of thesamples satisfies Condition A. Accordingly, in order to satisfyCondition A, the composition ratio of Au is only required to be lessthan 83 wt. %. Further, even if the composition ratio of Au is withinthis range, when the composition ratio of Pd reaches 35 wt. % as shownin Comparative Example 10-12, the sample does not satisfy Condition A.In contrast to this, when the composition ratio of Pd is less than 35wt. % as shown in Examples 10-1 to 10-27, any of the samples satisfiesCondition A. Accordingly, in order to satisfy Condition A, thecomposition ratio of Pd is only required to be less than 35 wt. %, andis preferably not more than about 34 wt. %.

[0377] Condition B)

[0378] Only the sample of Comparative Example 10-11 is insufficient andthe other samples are excellent in corrosion resistance. The sampleshown in Comparative Example 10-11 has a composition ratio of Ag at 49wt. %, and any of the other samples has a composition ratio of Ag atless than 49 wt. %. Accordingly, Condition B is satisfied when thecomposition ratio of Ag is less than 49 wt. %.

[0379] Condition C)

[0380] The samples satisfying both the aforementioned Conditions A and Bhave joining strengths of 590 MPa even at the minimum, and any of themexhibited a value better than those of the conventional brazing fillermetals. Accordingly, the samples satisfying both the aforementionedConditions A and B satisfy Condition C.

[0381] In consideration that the samples of Examples 10-24 and 10-25 arevery excellent in wettability against stainless steel, it is preferablethat at least one of Au and Ag satisfies the following conditions.

[0382] The composition ratio of Au is in a range of about 53 to about 56wt. %.

[0383] The composition ratio of Ag is in a range of about 5 to about 18wt. %.

[0384] As described in the foregoing, the Au—Ag—Cu—Pd—Ge—Si—Sn basedbrazing filler metal becomes a brazing filler metal satisfying all ofthe three requirements, that is, enabling low temperature joining andsecuring excellent corrosion resistance and sufficient joining strength,provided that the total composition ratio of Ge, Si, and Sn, and thecomposition ratios of Au and Pd fall within the ranges satisfyingCondition A, and the composition ratio of Ag falls within the rangesatisfying Condition B. Furthermore, provided that the composition ratioof at least one of Au and Ag is within the above-described range forexcellent wettability against stainless steel, the Au—Ag—Cu—Pd—Ge—Si—Snbased brazing filler metal is improved in wettability against stainlesssteel.

[0385] It is reasoned that since the Au—Ag—Cu—Pd—Ge—Si—Sn based brazingfiller metal is produced by adding Ge, Si, and Sn to Au—Ag—Cu—Pd, themelting point of the Au—Ag—Cu—Pd—Ge—Si—Sn based brazing filler metal islowest when the same has a composition utilizing any of five eutectics,that is, a eutectic of Ag Cu, a eutectic of Au—Ge, a eutectic of Ag—Ge,a eutectic of Cu—Ge, and a eutectic of Pd—Ge, similarly to the eighthbrazing filler metal, and additionally utilizing any of four eutectics,that is, a eutectic of Au—Si, a eutectic of Au—Sn, a eutectic of Ag—Si,and a eutectic of Ag—Sn. Therefore, the respective composition ratios ofAu, Ag, Cu, Pd, Ge, Si, and Sn, composing this brazing filler metal,have respective ranges required for obtaining the brazing filler metalas the object of the invention, and it is reasoned that the respectivecomposition ratios fall within the ranges found from the results of thetests shown in Tables 20 and 21 described above.

[0386] To sum up, it is reasoned that the Au—Ag—Cu—Pd—Ge—Si—Sn basedbrazing filler metal according to the invention is turned into a brazingfiller metal which is capable of low temperature joining and isexcellent both in joining strength and corrosion resistance, utilizingnine eutectics, that is, the eutectic of Ag—Cu, the eutectic of Au—Ge,the eutectic of Ag—Ge, the eutectic of Cu—Ge, the eutectic of Pd—Ge, theeutectic of Au—Si, the eutectic of Au—Sn, the eutectic of Ag—Si, and theeutectic of Ag—Sn, provided that the same satisfies all of the followingconditions 64) to 67).

[0387] Condition 64) The total composition ratio of Ge, Si, and Sn is ina range of more than 1 wt. % to less than 38 wt. %.

[0388] Condition 65) The composition ratio of Au is less than 83 wt. %.

[0389] Condition 66) The composition ratio of Pd is less than 35 wt. %.

[0390] Condition 67) The composition ratio of Ag is less than 49 wt. %.

[0391] Furthermore, the Au—Ag—Cu—Pd—Ge—Si—Sn based brazing filler metalcan be improved in wettability against stainless steel, provided thatthe same satisfies the following conditions 68) or 69).

[0392] Condition 68) The composition ratio of Au is in a range of about53 to about 56 wt. %.

[0393] Condition 69) The composition ratio of Ag is in a range of about5 to about 18 wt. %.

[0394] (Eleventh Brazing Filler Metal)

[0395] Subsequently, a Au—Ag—Cu—Pd—Ge—Si—Sn—Ni based brazing fillermetal which is an eleventh brazing filler metal according to theinvention is described hereinafter. This brazing filler metal iscomposed of Au, Ag, Cu, Pd, at least one kind of element out of Ge, Si,and Sn added thereto, and Ni added thereto. The eleventh brazing fillermetal is also different in element but is produced by the same method asthat of the first brazing filler metal.

[0396] Twenty-eight samples being Examples numbered from 11-1 to 11-28,shown in Table 22 and 13 samples being Comparative Examples numberedfrom 11-1 to 11-13 shown in Table 23, 41 samples, in total, of differentAu—Ag—Cu—Pd—Ge—Si—Sn—Ni based brazing filler metals, were prepared byvarying a composition ratio (wt. %) of each of Au, Ag, Cu, Pd, Ge, Si,Sn, and Ni as appropriate. The respective prepared samples were examinedin properties on the selected six items which are the same as those ofthe first brazing filler metal. It should be noted that the indicationof “Example” and “Comparative Example” is the same as that of the firstbrazing filler metal. The e) joining strength and f) corrosionresistance are checked in the same manner as that of the first brazingfiller metal.

[0397] As shown in Tables 22 and 23, the melting points of the samplesof Examples 11-1 to 11-28 are 753° C. (Example 11-15) even at themaximum, and the melting point of any of the samples is thus not higherthan 800° C. The melting points of the samples of Comparative Examples11-1 to 11-7, 11-9, 11-12, and 11-13, however, exceed 800° C. Regardingthe wettability against SUS316L, while the samples of Examples 11-1 to11-28 provided excellent results, the samples of Comparative Examplesother than Comparative Example 11-11 provided just slightly good resultswhich were not sufficient. Besides, the brazing temperature for any ofthe samples of Examples 11-1 to 11-28 was lower than 800° C. Crystalcoarsening of SUS316L occurred in the samples of Comparative Examples11-1 to 11-7, 11-9, 11-12, and 11-13, and not in the other samples. Thejoining strengths of the samples were 680 MPa even at the minimum, andany of them was better than those of the conventional brazing fillermetals. Regarding the corrosion resistance, any of the samples otherthan Comparative Example 11-11 exhibited an excellent result.

[0398] From the results shown in Tables 22 and 23, the conditions forthe Au—Ag—Cu—Pd—Ge—Si—Sn—Ni based brazing filler metal to satisfy theabove-described three conditions A, B and C, are as follows:

[0399] Condition A)

[0400] Since Comparative Examples 11-1 to 11-7, 11-9, 11-12, and 11-13and Examples 11-1 to 11-28 have common ranges of respective compositionratios of Au, Ag, and Cu, it is difficult to specify Condition A basedonly on the respective composition ratios of Au, Ag, and Cu.

[0401] Next, when the total composition ratio of Ge, Si, and Sn is nomore than 1 wt. % and when it is 37 wt. % as shown in ComparativeExamples 11-1 to 117, the melting points exceed 800° C., so that samplesthereof do not satisfy Condition A. However, any of samples satisfyingCondition A as shown in Example 11-1 to 11-28 has a total compositionratio of Ge, Si, and Sn which is in a range of more than 1 wt. % to lessthan 37 wt. %. Accordingly, in order to satisfy Condition A, the totalcomposition ratio of Ge, Si, and Sn needs to be in a range of more than1 wt. % to less than 37 wt. %. In this point of view, it can be said,particularly on the basis of values shown in Examples 11-1 to 11-28,that the total composition ratio of the Ge, Si, and Sn is preferably ina range of about 2 to about 36 wt. %. However, even if the totalcomposition ratio of Ge, Si, and Sn is within this range, when thecomposition ratio of Au reaches 74 wt. % as shown in Comparative Example11-9, the melting point exceeds 800° C., so that the sample does notsatisfy Condition A. In contrast to this, when the composition ratio ofAu is less than 74 wt. % as shown in Examples 11-1 to 11-28, any of thesamples satisfies Condition A. Accordingly, in order to satisfyCondition A, the composition ratio of Au is only required to be lessthan 74 wt. %. Further, even if the composition ratio of Au is withinthis range, when the composition ratio of Pd reaches 27 wt. % as shownin Example 11-12, the sample does not satisfy Condition A. In contrastto this, when the composition ratio of Pd is less than 27 wt. % as shownin Examples 11-1 to 11-28, any of the samples satisfies Condition A.Accordingly, in order to satisfy Condition A, the composition ratio ofPd needs to be less than 27 wt. %. Further, even if the compositionratio of Pd is within this range, when the composition ratio of Nireaches 18 wt. % as shown in Comparative Example 11-13, the sample doesnot satisfy Condition A. In contrast to this, when the composition ratioof Ni is less than 18 wt. % as shown in Examples 11-1 to 11-28, any ofthe samples satisfies Condition A.

[0402] Condition B)

[0403] Only the sample of Comparative Example 11-11 is insufficient andthe other samples are excellent in corrosion resistance. The sampleshown in Comparative Example 11-11 has a composition ratio of Ag at 47wt. %, and any of the other samples has a composition ratio of Ag atless than 47 wt. %.

[0404] Accordingly, Condition B is satisfied when the composition ratioof Ag is less than 47 wt. %.

[0405] Condition C)

[0406] The samples satisfying both the aforementioned Conditions A and Bhave joining strengths of 680 MPa even at the minimum, and any of themexhibited a value better than those of the conventional brazing fillermetals. Accordingly, the samples satisfying both the aforementionedConditions A and B satisfy Condition C. The Au—Ag—Cu—Pd—Ge—Si—Sn—Nibased brazing filler metal is excellent in joining strength than therespective tenth brazing filler metals. It is reasoned that this resultsfrom the addition of Ni.

[0407] In consideration that the samples of Examples 11-24 and 11-25 areexcellent in wettability against stainless steel, it is preferable thatAu and Ag satisfy the following conditions.

[0408] The composition ratio of Au is in a range of about 52 to about 54wt. %.

[0409] The composition ratio of Ag is in a range of about 5 to about 19wt. %.

[0410] As described in the foregoing, the Au—Ag—Cu—Pd—Ge—Si—Sn—Ni basedbrazing filler metal becomes a brazing filler metal satisfying all ofthe three requirements, that is, enabling low temperature joining andsecuring excellent corrosion resistance and sufficient joining strength,provided that the total composition ratio of Ge, Si, and Sn, and thecomposition ratios of Au, Pd, and Ni fall within the ranges satisfyingCondition A, and the composition ratio of Ag falls within the rangesatisfying Condition B. Furthermore, provided that the compositionratios of Au and Ag are respectively within the above-described rangesfor excellent wettability against stainless steel, theAu—Ag—Cu—Pd—Ge—Si—Sn—Ni based brazing filler metal is improved inwettability against stainless steel.

[0411] It is reasoned that the melting point of theAu—Ag—Cu—Pd—Ge—Si—Sn—Ni based brazing filler metal is lowered when thesame has a composition utilizing, similarly to the tenth brazing fillermetal, any of nine eutectics, that is, a eutectic of Ag—Cu, a eutecticof Au—Ge, a eutectic of Ag—Ge, a eutectic of Cu—Ge, a eutectic of Pd—Ge,a eutectic of Au—Si, a eutectic of Au—Sn, a eutectic of Ag Si, and aeutectic of Ag—Sn. Therefore, the respective composition ratios of Au,Ag, Cu, Pd, Ge, Si, Sn, and Ni, composing this brazing filler metal,have respective ranges required for obtaining the brazing filler metalas the object of the invention, and it is reasoned that the respectivecomposition ratios fall within the ranges found from the results of thetests shown in Tables 22 and 23 described above.

[0412] To sum up, it is reasoned that the Au—Ag—Cu—Pd—Ge—Si—Sn—Ni basedbrazing filler metal according to the invention is turned into a brazingfiller metal which is capable of low temperature joining and isexcellent both in joining strength and corrosion resistance, utilizingnine eutectics, that is, the eutectic of Ag—Cu, the eutectic of Au—Ge,the eutectic of Ag—Ge, the eutectic of Cu—Ge, the eutectic of Pd—Ge, theeutectic of Au—Si, the eutectic of Au—Sn, the eutectic of Ag—Si, and theeutectic of Ag—Sn, provided that the same satisfies the followingconditions 70) to 74).

[0413] Condition 70) The total composition ratio of Ge, Si, and Sn is ina range of more than 1 wt. % to less than 37 wt. %.

[0414] Condition 71) The composition ratio of Au is less than 74 wt. %.

[0415] Condition 72) The composition ratio of Pd is less than 27 wt. %.

[0416] Condition 73) The composition ratio of Ni is less than 18 wt. %.

[0417] Condition 74) The composition ratio of Ag is less than 47 wt. %.

[0418] Furthermore, the Au—Ag—Cu—Pd—Ge—Si—Sn—Ni based brazing fillermetal can be a preferable brazing filler metal having improvedwettability against stainless steel, provided that the same satisfiesboth the following conditions 75) and 76).

[0419] Condition 75) The composition ratio of Au is in a range of about52 to about 54 wt. %.

[0420] Condition 76) The composition ratio of Ag is in a range of about5 to about 19 wt. %.

[0421] (Joining of Components to a Case with the Brazing Filler Metal)

[0422] Now, with a case which is an exterior component of a timepiece,description is given hereinafter on a case of joining watch appearanceportions thereof to a case body with the brazing filler metals accordingto the invention.

[0423]FIG. 1 is a perspective view showing a case 2 fabricated byjoining 4 pieces of the watch appearance portions 3, 5, 7, and 9 to acase body 1 with the brazing filler metal according to the invention.The case body 1 comprises a sidewall made of stainless steel, formed inthe shape of a cylinder thin in wall thickness, and a bottom made ofstainless steel, and is polished so as to have a mirror-finished surfaceincluding contacting surfaces thereof, opposite to the watch appearanceportions. Each of the watch appearance portions 3, 5, 7, and 9, made ofstainless steel, is formed by applying grinding and polishing thereto,and the outside surface thereof except a contacting surface with thecase body 1, is polished so as to have a hairline finished surface.Further, each of the watch appearance portions 3, 5, 7, and 9 is workedon beforehand for drilling an end-piece hole 11 therein. The case body 1and the watch appearance portions 3, 5, 7, and 9 are formed by forging,respectively.

[0424] As shown in FIG. 2, a brazing filler metal 19 according to theinvention was sandwiched between the faying surface of the case body 1and that of the respective watch-appearance portions 3, 5, 7, and 9, andwas pressed into contact with the respective contacting surfaces beforesecured by tools (not shown). Thereafter, the case body 1 and respectivewatch appearance portions 3, 5, 7, and 9 were heated to a temperature atabout 650 to about 700° C. in a hydrogen reducing atmosphere for 20minutes, and subsequently, were rapidly cooled. The working of joiningwas conducted using the above-described first to eleventh brazing fillermetals for the brazing filler metal 19 to fabricate cases 2 with thefirst to eleventh brazing filler metals respectively. For example, thesample of Example 7-8 (Au at 50 wt. %, Ag at 9 wt. %, Cu at 9 wt. %, Inat 8 wt. %, Si at 7 wt. %, Pd at 7 wt. %, Mn at 1 wt. %, Li at 1 wt. %,and Ni at 8 wt. %) was used as the seventh brazing filler metal, and thesample of Example 8-7 (Au at 56 wt. %, Ag at 22 wt. %, Cu at 5 wt. %, Pdat 5 wt. %, and Ge at 12 wt. %) was used as the eighth brazing fillermetal. Further, the sample of Example 11-24 (Au at 54 wt. %, Ag at 5 wt.%, Cu at 6 wt. %, Ge at 7 wt. %, Si at 3 wt. %, Sn at 9 wt. %, Pd at 6wt. %, and Ni at 10 wt. %) was used as the eleventh brazing fillermetal.

[0425] As a result, there occurred full penetration of the brazingfiller metal 19 into joined portions between the case body 1 and therespective watch appearance portions 3, 5, 7 and 9, whereupon the case 2wherein the case body 1 was found fully integral with the respectivewatch appearance portions 3, 5, 7, and 9 in the external appearance wasobtained. With the case 2, a temperature at which the same was heatedwas not higher than the crystal coarsening temperature of the basemetals (800° C.), and consequently, the surface condition of thecomponents thereof, prior to joining, was found maintained withoutcausing the crystal structure of stainless steel to be coarsened,thereby forming clean interfaces between the case body 1 and therespective watch appearance portions 3, 5, 7 and 9. Furthermore, thejoined potions therebetween were able to have a sufficient tensilestrength (joining strength).

[0426] As described in the foregoing, if the metallic articles, that is,the case body 1 and the respective watch appearance portions 3, 5, 7 and9, are joined with each other by use of the brazing filler metalaccording to the invention, both the metallic articles can be joinedtogether in a preferable condition.

[0427] Meanwhile, in view of recent demand for expanding flexibility indesigning, there has been increasing requirement that a case body andrespective watch appearance portions are to be fabricated separately,and finished in a different surface condition, respectively. Forexample, the case body is to be finished so as to have a mirror-finishedsurface while the respective watch appearance portions are to befinished so as to have a hairline finished surface. However, since aconventional case has been fabricated as an integrally formed componentcomprising the respective watch appearance portions to be linked with abracelet, the conventional case has problems as follows:

[0428] First, the interface between case body and watch appearanceportion of the case is continuous surface by the integral formationthereof, it has been difficult to definitely identify the interfacesbetween the case body to be finished to have the mirror-finishedsurface, and the respective watch appearance portions to be finished tohave the hairline finished surface. In the case of forming asingle-piece case, it has an advantage in terms of cost to fabricate thesame by forging, however, there is then a drawback in that the shape ofthe respective watch appearance portions is subject to considerableconstraints in terms of designing.

[0429] On the other hand, the respective watch appearance portions needsto be provided with an end-piece hole for inserting a spring bar withwhich the bracelet is secured thereto, formed in a post-working processusing a drill, and there has been no choice but to drill the end-piecehole from the inside of the respective watch appearance portions not tobe seen from the outside for good external appearance of the case. Thedrilling of the end-piece hole from the inside of the respective watchappearance portions, however, has rendered a working for drilling theend-piece hole difficult to execute, and furthermore, the respectivewatch appearance portions, disposed opposite to each other, interferewith the working for drilling the end-piece hole, so that it has becomeimpossible to form the end-piece hole 11 vertically to a work face 7 aof the watch appearance portion 7, as shown in FIG. 5 by way of example,and consequently, there has been no choice but to form the same on theskew. For this-reason, there has arisen the need for forming theend-piece hole somewhat larger in size than the spring bar. This resultsin an excess clearance formed between the spring bar and the end-piecehole 11, and thereby creating a cause for the slack (rattle) of thespring bar.

[0430] As described hereinbefore, however, if the case body 1 is joinedto the respective watch appearance portions 3, 5, 7, and 9 by use of thebrazing filler metal according to the invention, it is possible toobtain the case 2 wherein both components thereof are found fullyintegral with each other in external appearance as well. This completelyprevents occurrence of the problems as encountered with the conventionalcase even if the case body 1 and respective watch appearance portions 3,5, 7, and 9 are fabricated separately and finished in different surfaceconditions, respectively.

[0431] The above-described first to eleventh brazing filler metals aredescribed taking, as examples, brazing filler metals using Ag and Cu asmetals having homogenously solubility with Au. In addition to Ag and Cu,Pt and Ni are also metals having homogenous solubility with Au, so thatplatinum (Pt) and Ni may be used in place of Ag and Cu.

[0432] In the above-described embodiments, since properties of thebrazing filler metals are examined with stainless steel members set asbase metals, the melting point not higher than 800° C. is set as thecondition required for obtaining the brazing filler metal of the objectof the invention. If a member made of a metal other than stainless steelis set as the base metal, its melting point is not necessarily limitedto 800° C.

[0433] In the foregoing, a kind of metal suitable for satisfactoryjoining to the other of the same by use of the brazing filler metalaccording to the invention is stainless steel. The brazing filler metalaccording to the invention is, however, adequate for application tovarious metals of which decorativeness in external appearance isrequired, for example, titanium metal and a titanium alloy.

[0434] In addition, the brazing filler metal according to the inventionhas no limitation in its shape. Considering convenience in executing ajoining work, the same is preferably produced in the shape of a sheet,foil, wire, and so forth. However, there can be cases where the brazingfiller metal is accompanied by brittleness to some extent, depending onthe chemical composition thereof. In this case the brazing filler metalmay be used after reducing the same to powders, and pressing the powdersfor molding.

[0435] A heating temperature at the time of brazing is in a range of 620to 800° C., preferably ranging from 650 to 750° C., brazing time ispreferably in the order of from about 5 minutes to about 1 hour, and anatmosphere in a furnace at the time of brazing is preferably a reducingatmosphere of hydrogen or the like or vacuum.

INDUSTRIAL APPLICABILITY

[0436] With the brazing filler metal according to the invention, joiningof metallic articles by brazing can be implemented at a temperature nothigher than the crystal coarsening temperature of the base metals, andsufficient joining strength as well as excellent corrosion resistance ofthe metallic articles joined together can be secured. Accordingly, thebrazing filler metal according to the invention is suitable for use inbrazing of metals such as stainless steel of which decorativeness inexternal appearance is required. TABLE 1 Au Ag Cu additive element a) b)c) d) e) f) Example 1-1 63 25 10 Si 507 560 ◯ no 610 ◯ 2 Example 1-2 7015  6 Si In 410 460 ◯ no 600 ◯ 4 5 Example 1-3 66  9  7 Ge Al Sb 590 640◯ no 610 ◯ 8 3 7 Example 1-4 58 11 10 Ge In Ga 533 580 ◯ no 600 ◯ 8 7 6Example 1-5 55 14  5 Bi Sn Te 572 620 ◯ no 620 ◯  4 15  7 Example 1-6 51 9  5 Pb Si Tl 557 610 ◯ no 600 ◯ 15  5 15 Example 1-7 35 25 20 Si In547 600 ◯ no 600 ◯  5 15 Example 1-8 55 15 10 Si In 525 580 ◯ no 610 ◯ 5 15 Example 1-9 79  6  2 Si In 662 710 ◯ no 620 ◯  4  9 Example 1-1064  6 10 Ge Sb 562 610 ⊚ no 620 ◯ 13  7 Example 1-11 47 20 13 Ge Sb 610660 ⊚ no 600 ◯ 13  7 Example 1-12 37 41  5 Ge Sb 664 710 ◯ no 600 ◯  9 8 (unit: wt %)

[0437] TABLE 2 Au Ag Cu additive element a) b) c) d) e) f) Comp Ex 1-159 25 15 Te 980 1030 Δ exist 590 ◯  1 Comp Ex 1-2 66 22 11 Bi 975 1030 Δexist 610 ◯  1 Comp Ex 1-3 51  7  6 Pb Si Tl 851  900 Δ exist 600 ◯  810 18 Comp Ex 1-4 51  7  6 Al In Te 832  880 Δ exist 600 ◯ 15 15  6 CompEx 1-5 34 25 20 Si In 593  640 Δ no 590 ◯  5 16 Comp Ex 1-6 80  6  2 SiIn 807  860 Δ exist 590 ◯  6  6 Comp Ex 1-7 65  5 10 Ge Sb 577  630 Δ no610 ◯ 13  7 Comp Ex 1-8 37 42  5 Ge Sb 701  750 ◯ no 600 X  8  8 (unit:wt %)

[0438] TABLE 3 brazing filler metal(wt %) a) b) c) d) e) f) Comp EX 1-9Ni_(82.45)Cr₇B₃Si_(4.5) 1050 1100 ◯ exist 580 ◯ Fe₃C_(0.05) Comp Ex 1-10Ag₅₈Cu₃₂Pd₁₀  850  900 Δ exist 530 X

[0439] TABLE 4 (unit: wt %) Sample Au Ag Cu Ge a) wettability againstSUS316L Example 2-1 85  4  6  5 714 ◯ Example 2-2 82  4  4 10 612 ◯Example 2-3 66  4  7 23 777 ◯ Example 2-4 35 30 25 10 780 ⊚ Example 2-560 15 15 10 741 ⊚ Example 2-6 80  5  5 10 720 ⊚ Example 2-7 70  6  5 19550 ⊚ Example 2-8 66 11 11 12 410 ⊚ Example 2-9 60 16  5 19 490 ⊚Example 2-10 40 40 10 10 700 ⊚ Comp Ex 2-1 86  4  6  4 815 Δ Comp Ex 2-269  4  3 24 810 Δ Comp Ex 2-3 34 31 25 10 832 Δ Comp Ex 2-4 81  8  4  7749 Δ Comp Ex 2-5 60  5 14 21 780 Δ Comp Ex 2-6 39 41 10 10 710 ◯ CompEx 2-7 30 35 25 10 782 Δ

[0440] TABLE 5 (unit: wt %) Sample Au Ag Cu Ge a) b) d) e) f) Example2-8 66 11 11 12 410 460 no 980 ◯ Example 2-9 60 16  5 19 490 540 no 880◯ Comp Ex 2-6 39 41 10 10 710 760 no 840 X Comp Ex 2-7 30 35 25 10 782830 exist 880 ◯

[0441] TABLE 6 (unit: wt %) wettability against Sample Au Ag Cu Si a)SUS316L Example 3-1 76 11 12 1 782 ◯ Example 3-2 78 9 10 3 692 ◯ Example3-3 80 5 5 10 713 ◯ Example 3-4 70 6 6 18 777 ◯ Example 3-5 41 29 20 10742 ⊚ Example 3-6 65 10 10 15 713 ⊚ Example 3-7 79 5 5 11 741 ⊚ Example3-8 65 5 22 8 721 ⊚ Example 3-9 72 12 12 4 663 ⊚ Example 3-10 67 17 12 4702 ⊚ Example 3-11 45 36 9 10 766 ⊚ Comp Ex 3-1 76.1 11 12 0.9 822 ◯Comp Ex 3-2 68 6 7 19 813 Δ Comp Ex 3-3 40 29 20 11 814 Δ Comp Ex 3-4 8010 5 5 761 Δ Comp Ex 3-5 64 4 22 10 810 Δ Comp Ex 3-6 44 37 9 10 731 ◯

[0442] TABLE 7 (unit: wt %) Sample Au Ag Cu Si a) b) d) e) f) Example3-9 72 12 12  4 663 710 no 890 ◯ Example 3-10 87 17 12  4 702 750 no 860◯ Comp Ex 3-5 64  4 22 10 810 860 exist 770 ◯ Comp Ex 3-6 44 37  9 10731 780 no 810 X

[0443] TABLE 8 Sample Au Ag Cu Ge Si Sn a) b) c) d) e) f) Example 4-1 7019  6  5 — — 730 780 ◯ no 610 ◯ Example 4-2 72 20  6 —  2 — 732 780 ◯ no620 ◯ Example 4-3 72 19  6 — —  3 738 790 ◯ no 650 ◯ Example 4-4 70 18 7  2  3 — 698 750 ◯ no 610 ◯ Example 4-5 74 14  7  3 —  2 743 790 ◯ no640 ◯ Example 4-6 72 16  7 —  3  2 693 740 ◯ no 610 ◯ Example 4-7 70 18 7  1  3  1 697 750 ◯ no 610 ◯ Example 4-8 69 14  4 13 — — 432 480 ◯ no630 ◯ Example 4-9 68 18  7 —  7 — 662 710 ◯ no 600 ◯ Example 4-10 67 17 5 — — 11 604 650 ◯ no 620 ◯ Example 4-11 67 16  5 10  2 — 462 510 ◯ no610 ◯ Example 4-12 67 16  5  9 —  3 481 530 ◯ no 600 ◯ Example 4-13 6716  5 —  6  6 641 690 ◯ no 600 ◯ Example 4-14 67 16  5  8  3  1 502 550◯ no 620 ◯ Example 4-15 67 15  5  7  4  2 511 560 ◯ no 620 ◯ Example4-16 66  7  7 20 — — 637 690 ◯ no 640 ◯ Example 4-17 64 11  9 — 16 — 741790 ◯ no 630 ◯ Example 4-18 58 10  5 — — 27 574 620 ◯ no 630 ◯ Example4-19 66  7  7 14  6 — 491 540 ◯ no 620 ◯ Example 4-20 60 10  8 12 — 10456 510 ◯ no 610 ◯ Example 4-21 62  6  5 —  8 19 502 550 ◯ no 600 ◯Example 4-22 56  8  2 14  3 17 603 650 ◯ no 600 ◯ Example 4-23 35 25 20 7  3 10 538 590 ◯ no 620 ◯ Example 4-24 53 17 10  7  3 10 497 550 ◯ no640 ◯ Example 4-25 79  6  2  5  3  5 651 700 ◯ no 640 ◯ Example 4-26 64 6 10  8  2 10 510 560 ⊚ no 640 ◯ Example 4-27 47 20 13  8  2 10 541 590⊚ no 660 ◯ Example 4-28 37 41  5  8  2  7 702 750 ◯ no 630 ◯ (unit: wt%)

[0444] TABLE 9 Sample Au Ag Cu Ge Si Sn a) b) c) d) e) f) Comp Ex 4-1 7915  5  1 — — 821 870 Δ exist 620 ◯ Comp Ex 4-2 79 15  5 —  1 — 803 850 Δexist 620 ◯ Comp Ex 4-3 79 15  5 — —  1 861 910 Δ exist 620 ◯ Comp Ex4-4 53  7  5 35 — — 815 870 Δ exist 610 ◯ Comp Ex 4-5 53  7  5 — 35 —862 910 Δ exist 640 ◯ Comp Ex 4-6 51  8  6 — — 35 830 880 Δ exist 600 ◯Comp Ex 4-7 55  6  4  2  6 27 867 920 Δ exist 610 ◯ Comp Ex 4-8 34 25 20 7  3 11 591 640 Δ no 610 ◯ Comp Ex 4-9 80  6  2  4  3  5 812 860 Δexist 600 ◯ Comp Ex 4-10 69  5  7  7  3  9 542 590 Δ no 610 ◯ Comp Ex4-11 40 42  3  5  3  7 733 780 ◯ no 640 X (unit: wt %)

[0445] TABLE 10 Au Ag Cu additive element Pd a) b) c) d) e) f) Element5-1 64 16 12 Ga  6 698 750 ◯ no 610 ◯  2 Example 5-2 68 10  6 Bi Si  8507 560 ◯ no 600 ◯  5  3 Example 5-3 59 10 10 In Ga Te  7 713 760 ◯ no610 ◯  5  5  4 Example 5-4 60  8  6 Al Ge Te  6 561 810 ◯ no 600 ◯  7  8 5 Example 5-5 53  7  7 Pb Sn  5 811 660 ◯ no 620 ◯ 10 15  3 Example 5-647  6  6 Sb Ge Te  4 698 750 ◯ no 600 ◯ 15 15  7 Example 5-7 34 18 13 SnBi  9 593 640 ◯ no 610 ◯ 18  8 Example 5-8 55 12  9 Al Ge  6 577 630 ◯no 620 ◯  9  9 Example 5-9 81  6  4 Ge Ga  3 724 770 ◯ no 620 ◯  4  2Example 5-10 56  5  7 Sn Sb  8 572 620 ⊚ no 580 ◯ 16  8 Example 5-11 5120  6 Ge Pb  6 544 590 ⊚ no 610 ◯ 10  7 Example 5-12 35 46  5 In Sn  6674 720 ◯ no 600 ◯  5  3 Example 5-13 35 14  6 In Tl 33 712 760 ◯ no 600◯  7  5   (unit: wt %)

[0446] TABLE 11 Au Ag Cu additive element Pd a) b) c) d) e) f) Comp Ex5-1 65 16 12 Al 6 981 1030 Δ exist 590 ◯ 1 Comp Ex 5-2 65 16 12 Bi 6 9771030 Δ exist 610 ◯ 1 Comp Ex 5-3 46 6 6 Ga Si Te 4 834 880 Δ exist 600 ◯15 15 8 Comp Ex 5-4 46 6 6 Te Ga Pb 4 983 1030 Δ exist 600 ◯ 9 20 9 CompEx 5-5 33 18 14 Sn Bi 9 614 660 Δ no 610 ◯ 18 8 Comp Ex 5-6 82 5 4 Ge Ga3 837 890 Δ exist 600 ◯ 4 2 Comp Ex 5-7 57 4 7 Sn Sb 8 543 590 Δ no 620◯ 16 8 Comp Ex 5-8 35 47 5 In Sn 5 741 790 ◯ no 590 x 5 3 Comp Ex 5-9 3513 6 In Tl 34 807 860 Δ exist 610 ◯ 7 5 (unit: wt %)

[0447] TABLE 12 first second Au Ag Cu additive element Pd additiveelement a) b) c) d) e) f) Example 6-1 63 14 13 Si 7 Mn 644 690 ⊚ no 600◯ 2 1 Example 6-2 67 8 6 Te Si 10 Li 510 560 ⊚ no 620 ◯ 5 3 1 Example6-3 60 14 6 Ge Sn Ga 4 Mn Li 639 690 ⊚ no 610 ◯ 5 5 4 1 1 Example 6-4 588 7 Al Sn Bi 5 Mn 522 570 ⊚ no 610 ◯ 7 7 6 2 Example 6-5 51 7 5 Ge Sn Sb7 Li 563 610 ⊚ no 600 ◯ 10 15 3 2 Example 6-6 45 6 4 Sb Sn Pb 6 Mn 633680 ⊚ no 610 ◯ 10 20 7 2 Example 6-7 34 19 12 Sn Al 7 Mn Li 542 590 ⊚ no600 ◯ 20 6 1 1 Example 6-8 51 11 10 Bi Ge 8 Mn Li 534 580 ⊚ no 610 ◯ 9 91 1 Example 6-9 77 6 4 Si In 5 Mn Li 644 690 ⊚ no 600 ◯ 3 3 1 1 Example6-10 56 6 6 Ge Pb 6 Mn Li 513 560 ⊚ no 610 ◯ 12 12 1 1 Example 6-11 4721 8 In Ga 5 Li 483 530 ⊚ no 590 ◯ 9 8 2 Example 6-12 35 47 5 In Sn 3 MnLi 643 690 ⊚ no 610 ◯ 5 3 1 1 Example 6-13 37 6 4 In Tl 31 Mn Li 644 690⊚ no 600 ◯ 17 3 1 1 (unit: wt %)

[0448] TABLE 13 first second Au Ag Cu additive element Pd additiveelement a) b) c) d) e) f) Comp Ex 6-1 61 14 14 Pb 8 Mn Li 920 970 Δexist 590 ◯ 1 1 1 Comp Ex 6-2 64 18 10 Sb 5 Mn Li 955 1010 Δ exist 600 ◯1 1 1 Comp Ex 6-3 43 6 4 In Ge Ga 7 Mn Li 833 880 Δ exist 610 ◯ 8 12 181 1 Comp Ex 6-4 41 6 6 Ga Si Al 7 Mn Li 943 990 Δ exist 610 ◯ 15 15 8 11 Comp Ex 6-5 33 20 12 Sn Al 7 Mn Li 563 610 Δ no 620 ◯ 20 6 1 1 Comp Ex6-6 78 6 4 Si In 4 Mn Li 807 860 Δ exist 620 ◯ 3 3 1 1 Comp Ex 6-7 57 56 Ge Pb 6 Mn Li 490 540 Δ no 610 ◯ 12 12 1 1 Comp Ex 6-8 34 48 5 In Sn 3Mn Li 641 690 ⊚ no 610 x 5 3 1 1 Comp Ex 6-9 36 6 4 In Tl 32 Mn Li 806860 ◯ exist 610 ◯ 17 3 1 1 Comp Ex 6-10 52 6 7 Sn Sb 8 Mn Li 813 860 ⊚exist 600 ◯ 16 8 2 1 Comp Ex 6-11 52 6 7 Sn Te 8 Mn Li 802 850 ⊚ exist600 ◯ 16 8 1 2 (unit: wt %)

[0449] TABLE 14 first second Au Ag Cu additive element Pd additiveelement Ni a) b) c) d) e) f) Example 7-1 58 11 18 Si 7 Li 3 728 780 ⊚ no690 ◯ 2 1 Example 7-2 58 11 9 Ge In 5 Mn 5 593 640 ⊚ no 660 ◯ 9 2 1Example 7-3 56 12 8 Pb Sn In 3 Mn Li 4 672 720 ⊚ no 710 ◯ 8 5 2 1 1Example 7-4 55 g 5 Sn Sb Bi 6 Mn 4 601 650 ⊚ no 700 ◯ 8 7 4 2 Example7-5 52 9 4 Ge Al Tl 4 Mn 3 666 720 ⊚ no 660 ◯ 10 9 7 2 Example 7-6 47 75 Bi In Si 3 Li 2 724 770 ⊚ no 680 ◯ 18 10 6 2 Example 7-7 36 15 12 GeBi 5 Mn Li 6 617 670 ⊚ no 680 ◯ 18 6 1 1 Example 7-8 50 9 9 In Si 7 MnLi 8 603 650 ⊚ no 670 ◯ 8 7 1 1 Example 7-9 73 7 4 Al Te 2 Mn Li 3 724770 ⊚ no 700 ◯ 5 4 1 1 Example 7-10 56 7 6 Sn Tl 7 Mn Li 5 607 660 ⊚ no680 ◯ 11 6 1 1 Example 7-11 41 25 8 Ga Al 5 Mn 4 550 600 ⊚ no 670 ◯ 11 42 Example 7-12 37 46 3 In Si 2 Mn Li 3 684 730 ⊚ no 700 ◯ 4 3 1 1Example 7-13 37 7 4 Bi Sb 30 Mn Li 3 711 760 ⊚ no 690 ◯ 13 4 1 1 Example7-14 49 8 5 Ge Te 6 Li 15 732 780 ⊚ no 690 ◯ 9 6 2 (unit: wt %)

[0450] TABLE 15 first second Au Ag Cu additive element Pd additiveelement Ni a) b) c) d) e) f) Comp Ex 7-1 63 13 10 Tl 7 Mn Li 4 987 1040Δ exist 640 ◯ 1 1 1 Comp Ex 7-2 63 18 5 Pb 4 Mn Li 7 1011 1060 Δ exist660 ◯ 1 1 1 Comp Ex 7-3 44 7 4 Si In Al 5 Mn Li 3 882 930 Δ exist 650 ◯17 10 8 1 1 Comp Ex 7-4 47 7 4 Bi Ga Ge 2 Mn Li 3 1001 1050 Δ exist 690◯ 14 12 9 1 1 Comp Ex 7-5 35 16 12 Ge Bi 5 Mn Li 6 603 650 Δ no 660 ◯ 186 1 1 Comp Ex 7-6 74 7 4 Al Te 2 Mn Li 2 928 980 Δ exist 680 ◯ 5 4 1 1Comp Ex 7-7 57 6 6 Sn Tl 7 Mn Li 5 582 630 Δ no 680 ◯ 11 6 1 1 Comp Ex7-8 36 47 3 In Si 2 Mn Li 3 733 780 ⊚ no 670 x 4 3 1 1 Comp Ex 7-9 36 74 Bi Sb 31 Mn Li 3 852 900 ◯ exist 690 ◯ 13 4 1 1 Comp Ex 7-10 49 7 7 SnSb 7 Mn Li 3 847 900 ⊚ exist 700 ◯ 16 8 2 1 Comp Ex 7-11 49 7 7 Ge Al 7Mn Li 3 838 890 ⊚ exist 670 ◯ 16 8 1 2 Comp Ex 7-12 49 8 5 Ge Te 5 Mn Li16 814 860 Δ exist 670 ◯ 9 6 1 1 (unit: wt %)

[0451] TABLE 16 (unit: wt %) wettability against Sample Au Ag Cu Pd Gea) SUS316L Example 8-1 50 11 5 29 5 732 ◯ Example 8-2 47 10 5 23 15 726◯ Example 8-3 44 11 8 12 25 740 ◯ Example 8-4 31 16 11 17 25 726 ⊚Example 8-5 75 5 6 6 8 703 ⊚ Example 8-6 75 5 6 6 8 720 ⊚ Example 8-7 5622 5 5 12 642 ⊚ Example 8-8 33 50 4 7 6 707 ⊚ Example 8-9 29 8 9 35 19733 ⊚ Comp Ex 8-1 51 11 5 29 4 812 Δ Comp Ex 8-2 43 11 8 12 26 805 ΔComp Ex 8-3 28 45 10 12 5 836 Δ Comp Ex 8-4 76 5 6 6 7 810 Δ Comp Ex 8-576 4 6 6 8 760 Δ Comp Ex 8-6 32 51 5 7 5 723 ◯ Comp Ex 8-7 31 10 10 3613 822 ◯

[0452] TABLE 17 (unit: wt %) Sample Au Ag Cu Pd Ge a) b) d) e) f)Example 8-7 56 22 5 5 12 642 690 no 870 ◯ Example 8-8 33 50 4 7 8 707760 no 860 ◯ Example 8-9 29 8 9 35 19 733 780 no 880 ◯ Comp Ex 8-5 76 46 6 8 760 810 exist 790 ◯ Comp Ex 8-6 32 51 5 7 5 723 770 no 730 x

[0453] TABLE 18 (unit: wt %) wettability against Sample Au Ag Cu Pd Sia) SUS316L Example 9-1 70 12 6 11 1 746 ◯ Example 9-2 71 13 2 4 10 723 ◯Example 9-3 66 7 7 4 16 744 ◯ Example 9-4 31 25 15 20 9 731 ⊚ Example9-5 71 11 5 5 8 722 ⊚ Example 9-6 70 3 8 9 10 716 ⊚ Example 9-7 57 19 1010 4 686 ⊚ Example 9-8 53 32 3 6 6 724 ⊚ Example 9-9 40 10 6 37 7 737 ⊚Comp Ex 9-1 64.1 15 9 11 0.9 810 Δ Comp Ex 9-2 65 7 7 4 17 823 Δ Comp Ex9-3 30 20 20 20 10 803 Δ Comp Ex 9-4 72 11 5 5 7 813 Δ Comp Ex 9-5 71 28 9 10 803 Δ Comp Ex 9-6 44 34 3 10 9 737 ◯ Comp Ex 9-7 39 10 6 38 7 811◯

[0454] TABLE 19 (unit: wt %) Sample Au Ag Cu Pd Si a) b) d) e) f)Example 9-7 57 19 10 10 4 686 740 no 820 ◯ Example 9-8 45 40 3 6 6 724780 no 880 ◯ Example 9-9 40 10 6 37 7 737 790 no 880 ◯ Comp Ex 9-5 71 28 9 10 803 850 exist 760 ◯ Comp Ex 9-6 44 34 3 10 9 737 790 no 800 x

[0455] TABLE 20 Sample Au Ag Cu Ge Si Sn Pd a) b) c) d) e) f) Example10-1 70 13 6 5 — — 6 741 790 ◯ no 630 ◯ Example 10-2 66 20 4 — 3 — 7 740790 ◯ no 670 ◯ Example 10-3 73 15 6 — — 2 4 743 790 ◯ no 680 ◯ Example10-4 63 9 5 2 3 — 18 731 780 ◯ no 640 ◯ Example 10-5 65 20 4 3 — 2 6 742790 ◯ no 640 ◯ Example 10-6 69 10 5 — 3 2 11 741 790 ◯ no 600 ◯ Example10-7 61 11 6 11 — — 11 512 560 ◯ no 610 ◯ Example 10-8 83 15 5 — 8 — 9551 600 ◯ no 590 ◯ Example 10-9 61 10 8 — — 14 7 547 600 ◯ no 600 ◯Example 10-10 65 7 5 10 3 — 10 508 560 ◯ no 600 ◯ Example 10-11 63 5 7 9— 4 12 526 580 ◯ no 640 ◯ Example 10-12 61 5 3 — 2 14 15 540 590 ◯ no610 ◯ Example 10-13 58 6 7 11 3 5 10 531 580 ◯ no 660 ◯ Example 10-14 587 7 20 — — 8 642 690 ◯ no 640 ◯ Example 10-15 68 6 8 — 15 — 5 742 790 ◯no 630 ◯ Example 10-16 56 6 5 — — 26 7 611 660 ◯ no 630 ◯ Example 10-1759 8 6 15 4 — 8 532 580 ◯ no 620 ◯ Example 10-18 58 7 8 12 — 10 5 530580 ◯ no 620 ◯ Example 10-19 55 5 4 — 5 20 11 551 600 ◯ no 600 ◯ Example10-20 50 5 5 13 4 20 3 502 550 ◯ no 610 ◯ Example 10-21 33 16 17 8 4 913 591 640 ◯ no 610 ◯ Example 10-22 55 6 7 6 3 11 12 532 580 ◯ no 620 ◯Example 10-23 82 5 2 4 3 3 1 691 740 ◯ no 620 ◯ Example 10-24 56 5 9 7 49 10 583 630 ⊚ no 610 ◯ Example 10-25 53 18 6 7 3 7 6 612 660 ⊚ no 610 ◯Example 10-26 34 48 2 5 3 4 4 735 790 ◯ no 610 ◯ Example 10-27 45 5 3 73 3 34 743 790 ◯ no 640 ◯ (unit: wt %)

[0456] TABLE 21 Sample Au Ag Cu Ge Si Sn Pd a) b) c) d) e) f) CompEx10-178 8 7 1 — — 6 851 900 Δ exist 600 ◯ CompEx10-2 78 8 7 — 1 — 6 820 870 Δexist 600 ◯ CompEx10-3 78 8 7 — — 1 6 873 920 Δ exist 640 ◯ CompEx10-451 5 4 38  — — 2 831 880 Δ exist 630 ◯ CompEx10-5 52 5 4 — 38  — 1 882930 Δ exist 630 ◯ CompEx10-6 50 5 5 — — 39  1 823 870 Δ exist 630 ◯CompEx10-7 46 8 4 3 8 27  4 903 950 Δ exist 620 ◯ CompEx10-8 32 14  17 10  4 10  13  612 660 Δ no 600 ◯ CompEx10-9 83 5 2 3 2 3 2 807 860 Δexist 630 ◯ CompEx10-10 57 4 9 7 4 9 10  590 640 Δ no 620 ◯ CompEx10-1134 49  2 5 3 4 3 731 780 ◯ no 630 X CompEx10-12 43 6 3 6 3 4 35  807 860Δ exist 600 ◯ (unit: wt %)

[0457] TABLE 22 Sample Au Ag Cu Ge Si Sn Pd Ni a) b) c) d) e) f)Example11-1 66 14  6 5 — — 5 4 748 800 ◯ no 710 ◯ Example11-2 64 18  5 —2 — 6 5 743 790 ◯ no 710 ◯ Example11-3 69 15  6 — — 3 4 3 743 790 ◯ no690 ◯ Example11-4 65 5 10  2 3 — 10  5 741 790 ◯ no 700 ◯ Example11-5 649 9 3 — 2 7 6 744 790 ◯ no 700 ◯ Example11-6 66 7 8 — 3 2 8 6 739 790 ◯no 710 ◯ Example11-7 60 8 8 11  — — 8 5 552 600 ◯ no 690 ◯ Example11-866 6 7 — 8 — 7 6 583 630 ◯ no 710 ◯ Example11-9 60 5 7 — — 14  6 8 595650 ◯ no 680 ◯ Example11-10 59 5 5 10  3 — 8 10  548 600 ◯ no 700 ◯Example11-11 60 6 7 9 — 4 10  4 577 630 ◯ no 710 ◯ Example11-12 60 5 5 —2 14  7 7 583 630 no 740 ◯ Example11-13 60 7 7 8 3 6 4 5 588 640 ◯ no700 ◯ Example11-14 54 8 7 20  — — 5 6 700 750 ◯ no 710 ◯ Example11-15 588 6 — 15  — 6 7 753 800 ◯ no 720 ◯ Example11-16 49 10  5 — — 25  7 4 632680 ◯ no 710 ◯ Example11-17 53 6 5 15  5 — 8 8 588 640 ◯ no 700 ◯Example11-18 52 8 7 12  — 10  7 4 591 640 ◯ no 710 ◯ Example11-19 48 7 8— 5 18  8 6 603 650 ◯ no 700 ◯ Example11-20 46 5 6 13  4 19  4 3 543 590◯ no 700 ◯ Example11-21 35 16  6 8 4 9 11  11  712 760 ◯ no 710 ◯Example11-22 61 8 6 7 3 7 4 4 599 650 ◯ no 760 ◯ Example11-23 73 5 4 4 35 3 3 744 790 ◯ no 760 ◯ Example11-24 54 5 6 7 3 9 6 10  613 660 ⊚ no720 ◯ Example11-25 52 19  5 8 3 5 4 4 655 710 ⊚ no 780 ◯ Example11-26 3646  3 4 4 2 2 3 741 790 ◯ no 710 ◯ Example11-27 35 5 6 10  3 10  26  5744 790 ◯ no 740 ◯ Example11-28 37 5 5 4 3 3 26  17  747 800 ◯ no 710 ◯(unit: wt %)

[0458] TABLE 23 Sample Au Ag Cu Ge Si Sn Pd Ni a) b) c) d) e) f)CompEx11-1 72 7 6 1 — — 7 7 903 950 Δ exist 730 ◯ CompEx11-2 72 7 6 — 1— 6 8 861 910 Δ exist 730 ◯ CompEx11-3 72 7 6 — — 1 7 7 910 960 Δ exist730 ◯ CompEx11-4 46 5 4 37  — — 5 3 876 930 Δ exist 720 ◯ CompEx11-5 435 4 — 37  — 4 7 914 960 Δ exist 740 ◯ CompEx11-6 43 5 4 — — 37  5 6 863910 Δ exist 740 ◯ CompEx11-7 41 5 4 5 6 26  3 10  933 980 Δ exist 710 ◯CompEx11-8 34 16  6 8 5 9 11  11  732 780 Δ no 730 ◯ CompEx11-9 74 6 2 34 3 2 6 806 860 Δ exist 720 ◯ CompEx11-10 55 4 5 8 3 9 6 10  621 670 Δno 730 ◯ CompEx11-11 36 47  3 4 3 2 2 3 743 790 ◯ no 730 X CompEx11-1238 7 6 5 4 5 27  8 811 860 Δ no 700 ◯ CompEx11-13 40 5 5 4 3 1 24  18 802 850 Δ no 700 ◯ (unit: wt %)

What is claimed is:
 1. (amended) A brazing filler metal having acomposition comprising gold, silver, copper, and an additive elementcomprising at least one kind of element out of aluminum, bismuth,gallium, indium, antimony, silicon, tin, lead, tellurium, and thallium,as main constituents thereof, wherein a total composition ratio of theadditive element is in a range of more than 1 wt. % to less than 36 wt.%, and a composition ratio of the gold is less than 80 wt. %, and acomposition ratio of the silver is less than 42 wt. %.
 2. A brazingfiller metal according to claim 1, wherein the total composition ratioof the additive element is in a range of about 2 to about 35 wt. %.
 3. Abrazing filler metal according to claim 1, wherein the composition ratioof the gold is more than 34 wt. %, and the composition ratio of thesilver is more than 5 wt. %.
 4. A brazing filler metal according toclaim 2, wherein the composition ratio of the gold is more than 34 wt.%, and the composition ratio of the silver is more than 5 wt. %.
 5. Abrazing filler metal according to claim 1, wherein the composition ratioof the silver is in a range of about 6 to about 41 wt. %.
 6. A brazingfiller metal according to claim 2, wherein the composition ratio of thesilver is in a range of about 6 to about 41 wt. %.
 7. A brazing fillermetal according to claim 1, wherein the composition ratio of the gold isin a range of about 47 to about 64 wt. %, and the composition ratio ofthe silver is in a range of about 6 to about 20 wt. %.
 8. A brazingfiller metal according to claim 2, wherein the composition ratio of thegold is in a range of about 47 to about 64 wt. %, and the compositionratio of the silver is in a range of about 6 to about 20 wt. %. 9.(cancelled)
 10. (cancelled)
 11. (cancelled)
 12. (cancelled) 13.(cancelled)
 14. (cancelled)
 15. A brazing filler metal having acomposition comprising gold, silver, copper, and silicon, as mainconstituents thereof, wherein a composition ratio of the silicon is in arange of more than 0.9 wt. % to less than 19 wt. %, a composition ratioof the gold is more than 40 wt. %, and a composition ratio of the silveris in a range of more than 4 wt. % to less than 37 wt. %.
 16. A brazingfiller metal according to claim 15, wherein the composition ratio of thesilicon is in a range of about 1 to about 18 wt. %.
 17. A brazing fillermetal according to claim 15, wherein the composition ratio of the goldis in a range of about 41 to about 79 wt. %, and the composition ratioof the silver is in a range of about 5 to about 36 wt. %.
 18. A brazingfiller metal according to claim 16, wherein the composition ratio of thegold is in a range of about 41 to about 79 wt. %, and the compositionratio of the silver is in a range of about 5 to about 36 wt. %. 19.(amended) A brazing filler metal having a composition comprising gold,silver, copper, and at least one kind of element out of silicon and tin,as main constituents thereof, wherein a total composition ratio of thesilicon and tin is in a range of more than 1 wt. % to less than 35 wt.%, a composition ratio of the gold is less than 80 wt. %, and acomposition ratio of the silver is less than 42 wt. %.
 20. (amended) Abrazing filler metal according to claim 19, wherein the totalcomposition ratio of the silicon and tin is in a range of about 2 toabout 34 wt %.
 21. A brazing filler metal according to claim 19, whereinthe composition ratio of the gold is in a range of about 47 to about 64wt. %, and the composition ratio of the silver is in a range of about 6to about 20 wt. %.
 22. A brazing filler metal according to claim 20,wherein the composition ratio of the gold is in a range of about 47 toabout 64 wt. %, and the composition ratio of the silver is in a range ofabout 6 to about 20 wt. %.
 23. (amended) A brazing filler metal having acomposition comprising gold, silver, copper, palladium, and an additiveelement comprising at least one kind of element out of aluminum,bismuth, germanium, antimony, silicon, tin, lead, tellurium, andthallium, as main constituents thereof, wherein a total compositionratio of the additive element is in a range of more than 1 wt. % to lessthan 38 wt. %, a composition ratio of the gold is less than 82 wt. %, acomposition ratio of the palladium is less than 34 wt. %, and acomposition ratio of the silver is less than 47 wt. %.
 24. A brazingfiller metal according to claim 23, wherein the composition ratio of thepalladium is not more than about 33 wt. %.
 25. A brazing filler metalaccording to claim 23, wherein the composition ratio of the gold is morethan 33 wt. %, and the composition ratio of the silver is more than 4wt. %.
 26. A brazing filler metal according to claim 24, wherein thecomposition ratio of the gold is more than 33 wt. %, and the compositionratio of the silver is more than 4 wt. %.
 27. A brazing filler metalaccording to claim 23, wherein the composition ratio of the gold is in arange of about 51 to about 56 wt. %, and the composition ratio of thesilver is in a range of about 5 to about 20 wt. %.
 28. A brazing fillermetal according to claim 24, wherein the composition ratio of the goldis in a range of about 51 to about 56 wt. %, and the composition ratioof the silver is in a range of about 5 to about 20 wt. %.
 29. A brazingfiller metal having a composition comprising gold, silver, copper,palladium, a first additive element comprising at least one kind ofelement out of aluminum, bismuth, gallium, germanium, indium, antimony,silicon, tin, lead, tellurium, and thallium, and a second additiveelement comprising at least one element out of lithium and manganese, asmain constituents thereof, wherein a total composition ratio of thefirst additive element is in a range of more than 1 wt. % to less than38 wt. %, a composition ratio of the gold is less than 78 wt. %, a totalcomposition ratio of the second additive element is less than 3 wt. %, acomposition ratio of the palladium is less than 32 wt. %, and acomposition ratio of the silver is less than 48 wt. %.
 30. A brazingfiller metal according to claim 29, wherein the total composition ratioof the first additive element is in a range of about 2 to about 37 wt.%.
 31. A brazing filler metal according to claim 29, wherein thecomposition ratio of the gold is more than 33 wt. %, and the compositionratio of the silver is more than 5 wt. %.
 32. A brazing filler metalaccording to claim 30, wherein the composition ratio of the gold is morethan 33 wt. %, and the composition ratio of the silver is more than 5wt. %.
 33. A brazing filler metal according to claim 29, wherein thecomposition ratio of the gold is in a range of about 34 to about 77 wt.%, and the composition ratio of the silver is in a range of about 6 toabout 47 wt. %.
 34. A brazing filler metal according to claim 30,wherein the composition ratio of the gold is in a range of about 34 toabout 77 wt. %, and the composition ratio of the silver is in a range ofabout 6 to about 47 wt. %.
 35. A brazing filler metal having acomposition comprising gold, silver, copper, palladium, nickel, a firstadditive element comprising at least one kind of element out ofaluminum, bismuth, gallium, germanium, indium, antimony, silicon, tin,lead, tellurium, and thallium, and a second additive element comprisingat least one element out of lithium and manganese, as main constituentsthereof, wherein a total composition ratio of the first additive elementis in a range of more than 1 wt. % to less than 35 wt. %, a compositionratio of the gold is less than 74 wt. %, a total composition ratio ofthe second additive element is less than 3 wt. %, a composition ratio ofthe palladium is less than 31 wt. %, a composition ratio of the nickelis less than 16 wt. %, and a composition ratio of the silver is lessthan 47 wt. %.
 36. A brazing filler metal according to claim 35, whereinthe total composition ratio of the first additive element is in a rangeof about 2 to about 34 wt. %.
 37. A brazing filler metal according toclaim 35, wherein the composition ratio of the gold is more than 35 wt.%, and the composition ratio of the silver is more than 6 wt. %.
 38. Abrazing filler metal according to claim 36, wherein the compositionratio of the gold is more than 35 wt. %, and the composition ratio ofthe silver is more than 6 wt. %.
 39. A brazing filler metal according toclaim 35, wherein the composition ratio of the gold is in a range ofabout 36 to about 73 wt. %, and the composition ratio of the silver isin a range of about 7 to about 46 wt. %.
 40. A brazing filler metalaccording to claim 36, wherein the composition ratio of the gold is in arange of about 36 to about 73 wt. %, and the composition ratio of thesilver is in a range of about 7 to about 46 wt. %.
 41. A brazing fillermetal having a composition comprising gold, silver, copper, palladium,and germanium, as main constituents thereof, wherein a composition ratioof the germanium is in a range of more than 4 wt. % to less than 26 wt.%, a composition ratio of the gold is in a range of more than 28 wt. %to less than 76 wt. %, a composition ratio of the palladium is less than36 wt. %, and a composition ratio of the silver is less than 51 wt. %.42. A brazing filler metal according to claim 41, wherein thecomposition ratio of the germanium is in a range of about 5 to about 25wt. %.
 43. A brazing filler metal according to claim 41, wherein thecomposition ratio of the gold is in a range of about 29 to about 75 wt.%, and the composition ratio of the silver is in a range of about 5 toabout 50 wt. %.
 44. A brazing filler metal according to claim 42,wherein the composition ratio of the gold is in a range of about 29 toabout 75 wt. %, and the composition ratio of the silver is in a range ofabout 5 to about 50 wt. %.
 45. A brazing filler metal having acomposition comprising gold, silver, copper, palladium, and silicon, asmain constituents thereof, wherein a composition ratio of the silicon isin a range of more than 0.9 wt. % to less than 17 wt. %, a compositionratio of the gold is in a range of more than 30 wt. % to less than 72wt. %, a composition ratio of the palladium is less than 38 wt. %, and acomposition ratio of the silver is in a range of more than 2 wt. % toless than 34 wt. %.
 46. A brazing filler metal according to claim 45,wherein the composition ratio of the silicon is in a range of about 1 toabout 16 wt. %.
 47. A brazing filler metal according to claim 45,wherein the composition ratio of the gold is in a range of about 40 toabout 71 wt. %, the composition ratio of the silver is in a range ofabout 3 to about 32 wt. %, and the composition ratio of the palladium isin a range of about 5 to about 37 wt. %.
 48. A brazing filler metalaccording to claim 46, wherein the composition ratio of the gold is in arange of about 40 to about 71 wt. %, the composition ratio of the silveris in a range of about 3 to about 32 wt. %, and the composition ratio ofthe palladium is in a range of about 5 to about 37 wt. %.
 49. A brazingfiller metal having a composition comprising gold, silver, copper,palladium, and at least any one kind of element out of germanium,silicon, and tin, as main constituents thereof, wherein a totalcomposition ratio of the germanium, silicon, and tin is in a range ofmore than 1 wt. % to less than 38 wt. %, a composition ratio of the goldis less than 83 wt. %, a composition ratio of the palladium is less than35 wt. %, and a composition ratio of the silver is less than 49 wt. %.50. A brazing filler metal according to claim 49, wherein the totalcomposition ratio of the germanium, silicon, and tin is in a range ofabout 2 to about 37 wt. %.
 51. A brazing filler metal according to claim49, wherein the composition ratio of the gold is in a range of about 53to about 56 wt. %, and the composition ratio of the silver is in a rangeof about 5 to about 18 wt. %.
 52. A brazing filler metal according toclaim 50, wherein the composition ratio of the gold is in a range ofabout 53 to about 56 wt. %, and the composition ratio of the silver isin a range of about 5 to about 18 wt. %.
 53. A brazing filler metalhaving a composition comprising gold, silver, copper, palladium, nickel,and at least any one kind of element out of germanium, silicon, and tin,as main constituents thereof, wherein a total composition ratio of thegermanium, silicon, and tin is in a range of more than 1 wt. % to lessthan 37 wt. %, a composition ratio of the gold is less than 74 wt. %, acomposition ratio of the palladium is less than 27 wt. %, a compositionratio of the nickel is less than 18 wt. %, and a composition ratio ofthe silver is less than 47 wt. %.
 54. A brazing filler metal accordingto claim 53, wherein the total composition ratio of the germanium,silicon, and tin is in a range of about 2 to about 36 wt. %.
 55. Abrazing filler metal according to claim 53, wherein the compositionratio of the gold is in a range of about 52 to about 54 wt. %, and thecomposition ratio of the silver is in a range of about 5 to about 19 wt.%.
 56. A brazing filler metal according to claim 54, wherein thecomposition ratio of the gold is in a range of about 52 to about 54 wt.%, and the composition ratio of the silver is in a range of about 5 toabout 19 wt. %.